State Police Crime Lab Tour: Fingerprinting and Tread Analysis

Climbing a mountain was pretty neat, but another highlight of my recent trip to Massachusetts was a tour of one of the regional Massachusetts State Police Crime labs. Many, many thanks to Detective Lieutenant Michael Holleran for making this tour of the Springfield lab happen. Detective Lieutenant Holleran was kind enough to be my technical advisor on fingerprinting past and present when we were writing TWO PARTS BLOODY MURDER, and he went to the trouble of setting up the tour, and then drove all the way across the state to meet and stay with us the entire time. Once again, we couldn’t write what we do without the generous help of the officers and staff of the Massachusetts State Police!

I was going to include all the information about the tour in a single blog post. But when the ever-stalwart Ann came back to me this ‘this blog post is toooooooo long’, I decided it needed to be cut into manageable chunks because this is very dense information. So, today, we’re going to cover crime scene services in the lab, primarily fingerprinting and casting. Next week will cover evidence handling and criminalistics. And then in our final week, we’ll cover ballistics, the largest section and truly deserving of a post of its own.

Detective Lieutenant Holleran (Crime Scene Services), Sergeant Ken Heffernan (Crime Scene Services), and Lieutenant John Crane (ballistics) took us through the Springfield crime lab that serves not only the Massachusetts State Police, but also many of the surrounding municipal forces. All three men are troopers who do everything in their area of the lab—they go out to the crime scene, gather evidence, and then return to the lab to analyze it. There are currently eight officers in the Springfield crime lab that are part of fingerprinting and crime scene services, and three officers in ballistics. All biological work in the criminalistics and biologics units, and much of the other testing (drug chemistry, arson, DNA, alcohol testing, and trace evidence) is performed by civilian forensic scientists.

Fingerprinting (part of Crime Scene Services): 

• All fingerprint evidence is handled in a designated fingerprint lab.

• Officers use a defined flowchart of test protocols to run on each print, starting at the top and working their way down, stopping after the first successful print development. Multiple tests can be run on the same print as long as the designated order is followed.

• UV light sources can be used to visualize prints on non-porous surfaces. Some prints can only be visualized and photographed this way; when they are chemically developed, no print appears.

• AFIS databases are accessed using MorphoTrak software. Massachusetts is the first state to link directly to the FBI database via third party software. Sergeant Heffernan ran one of his current cases for us—a break and enter with a fingerprint picked up through the mesh of a window screen. It took nine minutes for the resulting multi-point comparison match.

• Even after a positive AFIS result, the print must be confirmed by the human eye. In total, 3 officers must agree on the comparison for it to be considered a positive match.

• In the past, inked fingerprints have been standard, but over the last 10 years, live fingerprint scanning has gradually spread throughout the state. Troopers have live fingerprint scanners out in the field to be able to scan prints in situ instead of having to transfer evidence back to the lab. This kind of mobile fingerprinting also allows for faster identification of any deceased persons on scene.

• Live fingerprint scanners reject bad prints, but a good inked print will always have better resolution than a live scan, so troopers are still taught how to do classic inked prints by the Crime Scene Services officers since most troopers take their own perp prints out in the field.

Tread Analysis (part of Crime Scene Services):

• Casts are used to identify both shoe treads and tire tracks.

• Casts are taken using Denstone^®, a dental stone used for impressions because it has only 0.1% shrinkage with drying. Due to its ability to maintain its shape and size, it can be used for direct comparisons between the cast and the actual shoe or tire.

• Sergeant Heffernan feels that shoeprints are the most overlooked evidence and could be used much more effectively. For instance, the unique wear on shoes as well as any individual markings can be used to conclusively identify footwear present at the scene.

• There is an extensive tire tread database available for comparison. There is also a database for shoes, but it’s expensive because there are so many different types of shoes, and it must be constantly updated.

We’ll be back next week with a trip through the evidence room and the criminalistics lab. See you then!

Photo credit: Jessica Newton Photography

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The Seymour Agency’s 1st Literacy Fundraiser:

Naples, Florida (July 2014) - The Seymour Agency has announced it will be hosting a fundraiser to support the Literacy Council Gulf Coast through a national online auction taking place during the month of September. Industry editors, agents, and authors have donated critiques, phone chats, and goody packages as prizes.

Everyone deserves the time and means for the luxury of reading. Literacy Council Gulf Coast works with underprivileged youth and adults to provide quality literary education needed to function in today’s society.

The online auction will go live in phases on September 1, 2014 and bidding will end on September 30, 2014 at 11:59 p.m. with the largest bid received winning.

If you are not interested in the items up for auction, please consider a cash donation through CrowdRise. CrowdRise is a convenient way to donate money to charities.

Forensics 101: Digital Investigations and Cybercrime

The last of the forensics panels at Bloody Words XIII led us into the fascinating world of cybercrime. Our guide for the hour was digital forensics investigator Michael Perkin. Michael walked us through a couple of his cases (with all the specifics removed, of course) to give us a taste of how the bad guys were caught.

A case of defamation:

• A string of terrible allegations of was posted in a series of blog entries.

• The perpetrator then created a Gmail account to email the victim’s family, friends and colleagues links to the blog posts.

• Enter Michael. The first step in any digital investigation is the forensic acquisition of data. Never work from the original but make a full copy of all drives onto brand new, blank drives. Then the analysis can begin.

• Michael was able to analyze the email headers and trace the emails back to a specific internet provider. This is turn led back to the perpetrator, someone known to the victim.

• A judge  issued an ‘Anton Piller’ order—the search and seizure order from the civil side of law (as opposed to a standard criminal law order).

• The perpetrator had 30 minutes as the law allows to consult with his lawyer before the search could begin. He spent that entire time on his computer. When the computer was recovered, the desktop and documents folders on the hard drive were all blank. Except they really weren’t.

• Michael then drew the analogy of a hard drive being like a book (it was a writing conference after all!). The book has a table of contents and information on every page.

• The table of contents is what the computer considers the ‘master file table’—this keeps track of all the files on the computer.

• When the perpetrator deleted all the files, all he really did was remove the table of contents—the file index—leaving the information still in place.

• All Michael had to do was read through all the information on the drive and all the data required to convict the perpetrator was right there.

The complicated bounce:

• A computer at a company was suddenly locked out by a remote user.

• Michael came in to investigate, copied all the files, and analyzed the data.

• He discovered that the computer was accessed from another computer within the organization, which was accessed through another computer within the organization… rinse and repeat through numerous bounces.

• Michael was finally able to access the high value computer that was the actual target and discovered that data had been copied from it. But to where?

• In the end, it was the perpetrator’s printer that gave him up. No matter where he had bounced, each connection mapped back to his networked printer. So the final link in the chain could be mapped back to the perpetrator’s printer and, from there, to his computer and to him.

Bitcoin and its potential for cybercrime:

• Bitcoin is essentially a protocol. Just like email is a protocol to send messages over the Internet, Bitcoin is a protocol to send money over the Internet.

• Bitcoin has an address and a key, just like email has an address and a password. Both are an extremely long alphanumeric string.

• Bitcoin information can be stored on a computer, on a USB key, in a barcode, on a printout, or in your memory. This last is important as border crossings have a $10,000 limit to cross without reporting. But your Bitcoin account could contain millions of dollars and if you cross the border with the account and key memorized, you can circumvent reporting the money you ‘carry with you’.

• You can access your money from anywhere in the world. You can also send any amount of money to anywhere in the world.

• You could keep your printed Bitcoin key in a safety deposit box. Every time you deposit money into your Bitcoin account, you are essentially beaming it straight into that safety deposit box since it can’t be accessed without that key.

• People have accessed funds when in trouble simply by finding a public access—like television—and broadcasting their Bitcoin address in a 2D barcode with ‘Send Money’.

• Previous ID theft required a victim’s name, birthday, and social insurance number to steal your money. Now all that is required is your Bitcoin key.

Nifty facts about digital forensics:

• There are three types of space on a hard drive:

• Allocated space—sections of the drive used to hold files; these sections are listed in the table of contents/master file table.

• Unallocated space—sections of the drive that aren’t in use; these sections are not listed in the table of contents/master file table, but still may hold information.

• Slack space—Back to the book analogy: Suppose that a full page of information is deleted from the table of contents. That space is now considered unallocated. If half of that page is overwritten with new information (listed in the table of contents) the remaining half page of old information—the portion of the allocated space that is not used—is considered ‘slack space’.

• The only way to truly destroy data on a drive is to overwrite it multiple times. Data destruction software does this by simply writing 1’s and 0’s to the drive. Military protocol demands the drive be written over 10 times to consider the previous information truly ‘deleted’.

• If you truly need to secure your computer, take it off the internet and lock it in a room where only limited people have access through physical keys.

• Computers silently record everything we do through printer mapping, file edits, program usage and your browsing history (yes, even when you delete the cache). A skilled investigator can trace you through any of these pathways.

Photo credit: Benjamin Doe/Wikimedia Commons

Forensics 101: Fingerprinting Techniques

Today I’m continuing with my series of session reviews from Bloody Words XIII earlier this month in Toronto. I was interested in a session called CSI: Toronto, but when retired forensic identification specialist Wade Knaap arrived (with his graduate student apprentice) and started pulling out bottles of chemicals, I knew we were in for a treat. Sidenote—as a practicing scientist, I couldn’t help but wince every time Wade picked up his Tim Horton’s coffee in his gloved hand to take a sip. Just…no.

A Detective Constable for many years with the Toronto Police Service, Wade is now retired and teaching forensic identification at the University of Toronto. He spent an hour teaching us some of the tools of the trade when it came to fingerprint identification, specifically with latent prints—prints that are invisible to the naked eye until something is used to develop them.

First he dealt with fingerprints on a porous surface, i.e. paper, thermal cash register bills, currency.

Black magnetic powder: Investigators use a magnetic wand to pick up the fine magnetic powder (the powder comes in many shades, so there is always a contrasting shade available no matter what the background colour). The powder is gently swiped in a ciruclar motion over the latent print. The moisture in the print attracts the powder and the latent print is revealed. Unfortunately, any moisture will attract the powder in the same way, so if there is a latent print on a bottle with beer splashed over it, the powder will stick to the entire bottle. If a latent print is successfully detected and isolated, it can be lifted with tape to be photographed and entered into evidence.

Ninhydrin: This chemical reacts with the amino acids in fingerprints to produce a purple colour. A paper with a potential print is soaked in ninhydrin and allowed to air dry. Then the paper is exposed to steam. Any prints present will turn purple. These prints can then be further enhanced with a light source and photographed.

Wade then moved on to non-porous surfaces like a wall or solid object.

Cyanoacrylate (superglue): This is a popular one with the current forensics shows. You see them put an object with a potential print into a airtight box with a small tray of water and some superglue on a heated plate. As the plate temperature rises, the superglue vapourizes and the gaseous glue particles bind to the protein and amino acids in the fingerprint, polymerizing and plasticizing the print, creating a three dimensional permenant version. This procedure is very useful on handguns, where the gun oil required for regular maintenance would produce an extremely high background with most fingerprinting powders. If a dye is added to the superglue, a forensic light can be used to reveal the fingerprint. If the sample is in the field and can’t be moved into the lab, a portable cyanoacrylate torch can be used at the scene. However, great care must be taken as the temperature to vaporize the superglue is only somewhat below the temperature to produce deadly cyanide gas.

Amido black: This chemical is used solely for blood impressions that are too faint to see clearly or use for identifcation purposes. Faint impressions are sprayed with amido black and then the reaction is chemcially stopped. After a final rinse with water, the formerly faint impressions are a vivid permenant black.

Some fun facts about fingerprinting:

• Luminol is simply a blood locator that enhances small amounts of blood. It does not give big glowing prints like you commonly see in crime shows.

• Light sources can be very useful in finding bodily fluids. But unlike how this technique is fictiously used in crime shows, while it does light up semen or vaginal fluids, it will never light up blood spatter.

• None of the above tools are able to pull a reliable fingerprint from a live person without transferring that print first; there’s simply too much moisture. However you can do this from a cadaver using either magnetic powder or a process of iodine fuming and silver plate.

• Canada’s fingerprint database is run by the RCMP nationwide allowing for countrywide comparison. However, each state in the United States runs its own system, so to search outside an individual state, investigators must apply for national searches. A reciprocal agreement exists between Canada and the U.S to allow for open access for print searches between the two countries. Outside of Canada and the U.S., application must be made to Interpol for further searches.

• There are three types of prints: a deposited print (like a latent print from oily fingers), a takeaway impression (where, for instance, a dusty surface is touched and the dust is removed only from the point of contact), or a molded impression (if fingertips touch wet paint, leaving a 3D impression of the print behind).

• Canada recently issued new dollar bills made of polymer instead of paper. Porous techniques no longer apply to these new bills; instead, the superglue fuming technique must be used to develop latent prints.

• Unlike in CSI, overlapping prints cannot be taken apart and put back together to make a full print with multiple points of comparison. When prints overlap, the only parts of the print that are usable are the sections that are completely isolated and not in contact with any other print. This greatly decresases the chances of successfully identifying the print.

Next week, I’ll be back with my final forensics session review when I’m going to talk about cybercrime and the new threat presented by Bitcoin.

Forensics 101: A Primer on Blood

I’m recently back from the final Bloody Words crime writer’s conference, so, over the next few weeks, I’m going to share some of the fascinating information I learned at some of the panels I attended. This is the third time I’ve attended this conference, and while they always excelled at having lots of sessions pertaining to writing, they also had multiple sessions on forensics and procedure, taught by in-the-field professionals.

The first session of the conference was forensic hematology, presented by Margo French, a medical lab technologist. Margot has worked in the field of hematology (the study of blood, its cells and organs and blood-oriented diseases) for decades. She has been called as a trial witness on many occasions, so she’s familiar with lab techniques in criminal investigations.

Blood basics:

Blood can be broken down into two components—liquid and cellular. The liquid component, the plasma, makes up 55% of the total blood volume, with the combined cells making up the remaining 45%. 

Red blood cells (RBC):

• RBCs are the overwhelming cellular component in blood, making up about 60% of the total cellular volume. A single drop of blood has approximately 3.4 million RBCs.

• RBCs are the only cells in the body that are non-nucleated (have no DNA in the form of chromosomes). Cells develop in the bone marrow and start off having nuclei, but when they leave the marrow 7 days later, they are non-nucleated. Nucleated RBCs in the blood stream are destroyed by the spleen.

• RBCs live for approximately 120 days.

• The main purpose of RBCs is to carry oxygen to the tissues and carbon dioxide from the tissue. To accomplish this task, RBCs contain hemoglobin to bind the compounds for transfer within the body.

• The key to gas transport is the iron ions that are an integral part of the hemoglobin molecule. The iron you’re born with can stay with you for life, and is constantly recycled during your lifetime. When RBCs are destroyed, a type of white blood cell called a macrophage uptakes the iron and transports it back to the storage pool for reuse.

White blood cells (WBC):

• WBCs make up approximately 20% of the total cellular volume. A single drop of blood normally contains between 3,500 and 8,000 WBCs.

• The WBC complement is part of the human immune system and is made up of lymphocytes (including natural killer cells, T cells and B cells), basophils and eosinophils.

• WBCs vary in size based on cell type, but are generally about twice the size of a RBC.

• The life span of different WBCs also vary, but lymphocytes can live for years. Lymphocytes are the cells that recognize specific pathogens and, in the presence of a pathogen, will signal and then mount an immune response against it.

Platelets:

• Platelets are not intact cells. They are actually tiny pieces of cytoplasm from bone marrow cells called megakaryocytes.

• Platelets are approximately 1/4 the size of a RBC and 1/8 the size of a WBC.

• Platelets make up approximately 20% of the total cellular volume. Because of their size, a single drop of blood contains 150 – 400 million platelets.

• Platelets work with coagulation factors to stop bleeding. When the skin is cut, RBCs rushing to the site form a mesh. Platelets arrive at the site, swell, and become sticky. They then enter the mesh, filling the holes and creating a solid barrier, stopping the outward flow of blood.

Plasma:

• Composed of 95% water, plasma also contains proteins, clotting factors, hormones, electrolytes and glucose.

• Its main function is as the medium that holds the blood cells in suspension, and allows the flow and transport of cells, nutrients, and waste products around the body.

Some interesting facts about blood in criminal investigations:

• While thought to be a modern investigative tool, the chemical locator ‘Luminol’ dates back to 1901.

• The first time blood analysis was used as part of an investigation was in 1937.

• Blood and fingerprinting used to be an investigator’s primary identification tools. But both techniques have been eclipsed in recent years by DNA, as this is the only technique which can completely exclude a suspect (all other tests have a certain percentage of false negatives).

• Information carried in the blood can denote blood type to include or exclude suspect. DNA obtained from white blood cells can be used for definitive identification.

• The difference between many species and human blood is not easily discernable, so serology—the study of human plasma—is used to identify human blood.

• Blood is also used for chemical testing, i.e. blood alcohol and bloody glucose analysis.

• While not covered in this blog post, blood at a crime scene can indicate the mechanics of the crime, i.e. bloody carrying or spatter.

 Next week, we’re going to look at fingerprinting techniques, especially when investigators are faced with latent (invisible) prints.

Forensic Case Files: How Shakespeare Changed History (or The Continuing Story of Richard III)

A 3D approximation of the articulated skeleton of Richard IIIIt’s a story we’ve been following for a while. In October of 2012, we covered the discovery of historic human remains under a parking lot in Leicester. Because of the physical characteristics of those remains—primarily an extremely curved spinal column—it was suggested that they were the remains of King Richard III, killed at the Battle of Bosworth Field, during the War of the Roses against Henry Tudor (later Henry VII and the beginning of the Tudor line that would include Henry VIII and Queen Elizabeth I). In February of 2013, it was confirmed that those remains were indeed those of Richard III when scientists successfully matched his mitochondrial DNA—DNA consistently passed only through the female line of a family—to the mitochondrial DNA of relatives through Richard’s sister’s line.

Just last week, the University of Leicester announced that it had completed its studies on Richard’s spinal column and determined that the king’s spine showed 65 to 85 degrees of scoliosis, curving the spine to his right. A modern day patient with that degree of scoliosis would be an excellent candidate for surgery; in the fifteenth century, this was not yet an option. However, with the skilled help of both a tailor and master armorer, the deformity could have been minimized or even completely camouflaged (minus one shoulder sitting slightly higher than the other). Richard’s skeletal remains also show no evidence of a withered arm or a limp, both part of the Richard III legend. In fact, one needs to keep in mind that Richard was a skilled soldier, able to fight on horseback with both sword and shield—an act someone with a major deformity might not be able accomplish.

It is clear now that Richard, while having a spinal deformity, was never a hunchback. So where did that picture of the king come from? No mention is made of Richard the hunchback until 1598 by Shakespeare: First in Henry VI: “an envious mountain on my back, / Where sits deformity to mock my body” (Act 3, scene ii) and later in Richard III, where Queen Elizabeth describes him as “that foule hunch-backt toade” (Act 4, scene iv). But considering that Shakespeare wasn’t a contemporary of Richard III, and was, in fact, born nearly 100 years after Richard’s death, where did this information come from? From the men who were writing the history of the time—the Tudors—who had a vested interest in showing Richard in the most negative light possible.

History is written by the victors. In this case, the Tudors used The Bard to smear a predecessor so successfully that over 400 years later, that unsupported history still lingers and, for many, the view of Richard as a hunchbacked monster responsible for the death of his two nephews, The Princes in the Tower, remains to this day.

Photo credit: The University of Leicester

Forensic Case Files: 13,000 Year Old Skeleton Shines Light on the Geographic Origins of North American Peoples

An article last week in the journal Science revealed the discovery of a 12,000 year old skeleton in Mexico, one of the oldest human remains discovered in North America. The article made a big splash on campus at McMaster University as one of the researchers, Ed Reinhardt, is a Geography and Earth Sciences professor here.

Twelve thousand years ago, much of North America was covered by glaciers. But Mexico was free of the glaciers’ icy hold, making it a suitable habitat for some of North America’s indigenous people. One particular group settled on the coast of what is now known as the Yucatan peninsula.

What happened that one day so many millennia is clear; CSI couldn’t have put it together better. A teenaged girl of 15 or 16 years of age was exploring a subterranean cave, perhaps with only the light of a torch, probably searching for fresh water. When the ground suddenly fell away beneath her feet, she fell more than 160 feet to her death. It was an all-too-common mistake—her remains were found mixed with those of a saber tooth tiger, a giant ground sloth, a bobcat, a coyote, and a gomphothere (an elephant-like creature, extinct for approximately 9,000 years).

As the glaciers receded, and the sea levels rose, the cave system filled with salt water, entombing those lost in the dark below. But science recently discovered the cave systems and experienced divers, Dr. Reinhardt among them, retrieved the girl’s remains. The girl, christened Naia by the team, was determined to have lived between 12,600 and 12,900 years ago not only by her own remains, but also by the rocks and sediment recovered around her.

The most fascinating data to come from the study of this young woman concerns her heritage. Researchers extracted ancient tooth pulp from one of her molars (in a similar method as used to identify the plague from Black Death victims) to profile her mitochondrial DNA. Researchers discovered that Naia was not only related to modern North American aboriginal peoples, but also to the Siberian-based population from which is it believed that all indigenous North Americans arose.

The shape of Naia’s skull is distinctly different from modern North American aboriginals, indicating that while the their common ancestors crossed the narrow land bridge to North America, traveling between North America’s dual glaciers to settled in Central America, genetically, the two peoples evolved different phenotypic characteristics afterward.

Scientists are now attempting to sequence Naia’s entire genome to discover what other genetic connections this long lost girl might reveal to modern man.

Photo credit: Roberto Chavez Arce and Science

Forensic Case Files: 9/11 Victims' Final Resting Place

Last year, we did a series of blog posts on 9/11—mass fatality accidents, identifying human remains, the challenges in naming the victims, and the ongoing evidence still being uncovered around the site. A little over a week ago, on May 10^th, one of the final chapters of the 9/11 story was written as the final unidentified victims were moved back to Ground Zero to become part of the September 11^th Memorial Museum, a permanent part of the Ground Zero site.

Thirteen years after the tragedy, 1,115 or 41% of the 2,753 lost souls have yet to be positively identified by DNA, despite the fact the Office of the Chief Medical Examiner of the City of New York held 7,930 fragmentary samples of unmatched human remains. Due to the condition of these samples—many were badly degraded by the heat of the fire or ground to less than a 1/16” in size during the building collapses—DNA testing was either impossible or inconclusive, despite the samples given by family members for comparison.

Enclosed in three caskets, these final unidentified remains were escorted in the early morning hours through the streets of New York City by an honour guard made up from members of the New York Fire Department, the New York Police Department, and the New York Port Authority. Upon arriving at Ground Zero, they were transferred to a repository at bedrock level in the museum, 70 feet below the street. Walled off from the exhibition space, only staff of the medical examiner’s office and family members will be allowed access to the facility.

The decision to make this the victims’ final resting place raises mixed emotions in family members of those lost. Many feel the final remains of their loved ones have become part of a ‘dog-and-pony show’ tourist attraction, and have also raised concerns about the possibilities of flooding in the subterranean location. But many others feel that Ground Zero is an appropriate resting place for the victims that lost their lives there, that the museum is a place of reflection, respect and education, and the victims are a crucial part of the 9/11 experience.

Forensic scientists remain hopeful that these remains may yet be identified. New scientific techniques are constantly being developed, and many samples that would have been impossible to identify in 2001 are now excellent candidates for matching. The hope is, given time and scientific advances, many more of the remaining fragments will be identified and the victims finally returned to their families.

As an aside, for those who are interested, The New York Times has an excellent interactive tour of the museum here: http://www.nytimes.com/interactive/2014/05/14/arts/design/September-11-Memorial-Museum.html. It's well worth the time to read.

Photo credit: Peter Foley/European Pressphoto Agency

Forensics 101: Forensic Dentistry

Following last week’s post about determining a victim’s age at the time of death using their teeth, it seemed appropriate to take a brief look at the field of forensic dentistry (also called forensic odontology). Here on Skeleton Keys, we tend to focus more on forensic anthropology as that is the science of Dr. Matt Lowell of the Abbott and Lowell Forensic Mysteries, but forensic dentistry is an important field that is often used in conjunction with forensic anthropology.

Forensic dentistry is the application of the practice of dentistry in criminal investigations. Often, the type of remains that leave investigators requiring the services of a forensic anthropologist may also benefit from a forensic dentist, and the two scientists will often work cases side-by-side. Forensic dentists work by comparing antemortem (before death) dental records and x-rays with post-mortem (after death) remains. They are often involved in mass casualty incidents when remains are too decomposed, damaged or fragmented for more standard identification procedures like fingerprinting or DNA.

In 2010, when I attended the Bloody Words mystery conference in Toronto, I was fortunate enough to sit in on a lecture from Dr. Ross Barlow called ‘Teeth Talk: The World of Forensic Dentistry’. Dr. Barlow had been involved in the identification efforts following the 2004 Boxing Day Tsunami that devastated South Asia. Forensic dentists were called in to assist, not because of the initial nature of the remains, but because of the sheer number of bodies (130,000 in Indonesia alone), and the inability to refrigerate the corpses in the tropical heat. Decomposition became a major complicating factor, so skeletal component identification was one of the most successful methods of identification.

Victim identification is the overwhelming task of a forensic dentist, comprising approximately 95% of their cases. But forensic dentists contribute on multiple levels to criminal investigations:

• Victim age at time of death: As mentioned last week, aging a victim based on tooth eruption and development.

• Bite mark assessment: Bite marks are common in cases of aggravated assault and abuse. Forensic dentists assess and compare the marks on a victim with the bite pattern of a potential assailant. Also, while the field of veterinary forensic science (including odontology) is in its infancy, human forensic dentists are often involved in criminal prosecutions resulting from dog attacks and the prosecution of dog-fighting rings to match dog bite marks to individual dogs.

• Identification of remains: Identification is based on both common and unique gross tooth characteristics, as well as past dental work, including fixtures and fillings.

• Identification of fire-damaged remains: During extensive fire exposure, the front teeth are the first to be lost. Tooth enamel dehydrates and sloughs off the dentin. But identification can be determined in severely damaged remains by antemortem root canals and matching antemortem fillings.

• Race determination: As we discussed when covering race determination from skull attributes, the incisors of people of Asian or native descent are shovel-shaped with ridges on the rear surface of the tooth. Those of white or black descent, have blade form incisors with a flat profile.

Like forensic anthropologists, forensic dentists are often called in to view the most badly damaged or decomposed remains. Working with investigators, they can indicate or confirm identification, or assist in trauma assessment. In mass casualty disasters, such as 9/11, floods, earthquakes, tsunamis or plane crashes, they may be the only ones able to identify the dead, giving them back their names, and allowing their families much needed closure.

Photo credit: Wikimedia Commons

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Forensics 101: Determining Age at Death Using Dentition

When it comes to unknown victim identification, there are three main pieces of information a forensic anthropologist can contribute to an investigation—sex, race, and age at the time of death. In some cases, time since death can also assist in narrowing victim identification based upon reports of the last time the victim was seen alive. Previously, we’ve covered various ways to determine the victim’s age at the time of death based on epiphyseal fusion or the adult pelvis, but several other methods exist and are also in use. One of the least sexy—but most useful—ways to determine age at the time of death is to use the victim’s teeth.

This method relies on the fact that, throughout childhood, baby teeth are lost and new teeth erupt according to fairly predictable developmental time points. Even more so than epiphyseal fusion, tooth loss and gain holds to a more rigorous chronological schedule.

There are four notable time periods of tooth development in growing children:

• Deciduous baby teeth emerge during the first two years of life.

• The first two permanent incisors and the first permanent molar emerge between 6 and 8 years of age.

• The majority of the remaining permanent teeth erupt between the ages of 10 and 12 years of age.

• Wisdom teeth tend to erupt around 18 years of age.

In addition, the development of permanent teeth within the skull before eruption occurs can help indicate age. This can be clearly seen in x-rays taken by a coroner or medical examiner.

Using dentition to age adults is a more challenging practice. Once the wisdom teeth have erupted, only morphological changes within the teeth indicate age differences. These changes can include:

• Tooth root translucency increases with age, independent of periodontal damage.

• Dental wear on the teeth; this tends to be a predictable variable within populations.

• Ratio of the amino acids D-aspartic acid to L-aspartic acid in tooth dentin. The L form of any amino acid is the mirrored structural image of the D form. Amino acids begin in the L form and convert with age to the D form, so a preponderance of the D form indicates increasing age. 

Especially in children, the use of dentition can be very helpful in victim identification by minimizing the estimated age range. Used in conjunction with other methods, such as epiphyseal fusion, forensic anthropologists can be quite exact in providing age related information to investigators.

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Photo credit: Wikimedia Commons (skull section) and Wikimedia Commons (developing teeth)

Forensic Case Files: Hidden Bodies Discovered at the Dozier School for Boys

The Arthur G. Dozier School for Boys in Marianna, Florida was at one time the largest juvenile reform school in the United States, housing up to 564 boys in the 1960s. Founded in 1900, the school went through a number of identity changes over the years—first called the Florida State Reform School, then the Florida Industrial School for Boys (1914), later the Florida School for Boys (1957), and finally the Arthur G. Dozier School for Boys (1967) named in honour of a past superintendent of the school.

Rumours of inhumane treatment of the inmates plagued the school from the very beginning. An inspection in 1903 reported some boys being kept in leg irons, and, in 1934, a boy sent to the school on a trespassing charge died a mere 38 days later. Hundreds of more recent allegations detailed years of beatings, forced labour, rape, and the murder of troublesome inmates. Many boys simply disappeared after arriving at the school, no trace of them alive or dead ever discovered. Amid a storm of unproven accusations and controversy, the state of Florida permanently closed the facility in 2011.

But public outcry persisted and families demanded answers about their missing relatives. Thirty-one white metal crosses marking the graves in the school cemetery didn’t account for all the missing children. Confusing and incomplete school records meant that investigators were not even sure of the exact number of bodies buried in the cemetery.

University of South Florida forensic anthropologist Erin Kimmerle became interested in the project, in part because of the inadequate record keeping at the school—very unusual for most state institutions. In 2012, Kimmerle and her team used ground penetrating radar and cadaver dogs to prove the existence of at least 50 sets of remains buried on school property, many located under current roads or overgrown trees, far distant from the marked cemetery. A full investigation of the property began in August 2013.

Excavations of the school grounds began in the fall of 2013. By the time the dig closed three months later in December, 55 bodies had already been recovered. Anthropologists estimate that the bodies date from the late 1920s to the early 1950s. All the remains were found in coffins or associated with coffin artifacts—nails or other hardware, and one with a brass plaque reading ‘At Rest’. Some small artifacts of life at the school were also recovered; one boy was even found with a stone marble still in his pocket.

Forensic scientists will attempt to determine cause of death from the skeletal remains, and DNA from the recovered remains will be sent to the University of North Texas Center for Human Identification. Investigators are asking for living family members of missing students to come forward and provide DNA samples for reference and comparison.

Although the first dig is complete, University of South Florida anthropologists are planning to resume work in the spring of 2014. They believe the site holds the remains of more missing boys, and maybe even a second unmarked cemetery. Their search will continue until investigators are satisfied that all the lost have been recovered. Although the Florida Department of Law Enforcement was unable to substantiate the multiple claims of abuse while the school was open, they are hoping that this time the dead will be able to speak for themselves.

Photo credit: Robert Straley

Forensic Case Files: 16th Century Vampire Burials

Modern sensibilities and science tell us that there is no such thing as vampires (especially not sparkly ones!). But to people of the Middle and early Modern Ages, vampires were a real fear. The belief in vampires likely evolved because people of the time didn’t understand the natural process of decomposition, including corpse bloating and fluid purging. To protect themselves from the undead, communities adopted specific burial practices:

• Four skeletons were recovered this past July in Poland during a road construction project. Each set of remains was found with the head buried between the legs. Since the bodies were buried without personal effects, dating of the remains is proving difficult, but, with further testing, scientists hope to confirm their estimate of a fifteenth or sixteenth century burial. During that period, suspected vampires would be ritually executed by decapitation, or they would be hung until decomposition naturally rotted the neck tissues and the weight of the body pulled it from the head. The belief was that a vampire would not be able to rise if it couldn’t locate its own head.

• In Bulgaria, a number of skeletons have been discovered with an iron rod through the heart and their teeth removed. This ritual provided two-fold protection: The iron rod pinned the dead into the grave, preventing them from rising. But in case they did manage to escape, removal of the teeth ensured that the undead would not be able to feast on flesh of the living.

• The Black Plague killed over 50,000 residents of Venice in the year 1576, including the medieval artist Titian. Four hundred and thirty-three years later, Italian researcher Matteo Borrini and his team were excavating a mass grave from the epidemic when they discovered a peculiar victim—a dead woman with a brick wedged between her teeth. Dr. Borrini hypothesized that the practice of opening up mass graves to add more victims, thereby exposing the decomposing bodies, led people to believe that vampires were spreading the plague by chewing on their death shrouds. Bricks were placed in the mouths of these ‘Shroud Eaters’ to stop them from spreading disease.

What appears as odd customs to modern people were reinforced to those early believers as the ‘vampires’ never rose from the grave. And looking at it from a modern perspective, it’s clear where some of the customs around current vampire traditions arose. So the next time you see a vampire movie, remember that some of those mythical aspects date back centuries to a time when society was looking for simple answers to explain complex biology.

Photo credit: Andrzej Grygiel/EPA, Nikolay Doychinov/ AFP and Matteo Borrini

Forensics 101: Mass Grave Methodology

The first hurdle to overcome in mass grave investigations is determining the location of the grave. As we discussed last week, mass graves are deliberately hidden to avoid detection, so simply finding the grave is the crucial first step. To further complicate the process, there are often one or more satellite sites associated with mass graves:

• the execution site (either a surface execution site or a site within the grave itself)

• temporary surface deposition sites used during the transfer of remains from primary to secondary and tertiary sites.

But once the final grave is discovered, how do investigators proceed with an excavation that has to unearth and account for all the evidence in the grave without losing any important information?

There are two main methods used to excavate a mass grave:

Pedestal method:

• The soil around the body mass is removed to just below the lower boundary of the grave, allowing complete viewing from all angles and access to all bodies along the outer margins and top of the grave.

• The original grave walls and ramp are destroyed, but investigators do not have to stand on bodies during the excavation process since workers start at the outer boundaries and work inward.

• This formation allows for water drainage from the site and more complete in situ photography while bodies are still in place.

• The main disadvantage to this method is the loss of stability conferred by the earth surrounding the grave. If the central mass erodes, bodies and body parts can become displaced.

Stratigraphic method:

• The grave is treated as a single site: bodies and artifacts are excavated from top to bottom, removing evidence in reverse order to which it was deposited into the grave.

• Grave walls and ramps are retained, leading to a better understanding of how the grave was constructed. Tool marks and tire tracks may also be recovered.

• Due to the even lowering of the surface grave, rainwater can pool within the confines of the grave, damaging exposed remains or eroding the body mass, but tents or shelters can be constructed over the grave to protect it during inclement weather.

• Only bodies on the top of the mass can be accessed or viewed.

• The bodies must be walked on by the investigators during the course of the excavation.

So which method is better?

• Bones are separated from the body during both methods, although larger bones tends to be dissociated in the pedestal method and smaller bones in the stratigraphic method. Thus the stratigraphic method results in more complete body recoveries.

• Decomposition tends to progress faster in bodies on the outer edges of the grave. The pedestal method exposes those bodies, leading to erosion of the mass and possible mixing of the remains.

• Secondary or tertiary graves tend to contain more skeletonized remains and increased dissociation. Use of the pedestal method seems to accelerate slumping of the grave mass.

As a result, current scientific opinion is that the stratigraphic method is preferable where possible.

Photo credit: Gilles Peress and Press Association

I’m going to take a break from blogging for the next few weeks to enjoy the summer holidays and visiting family, but we’ll be back on August 20th with all new content. See you then!

Forensics 101: Forensic Challenges of Mass Grave Excavations

Last week we marked the 18^th anniversary of the massacre of 8,100 Bosniak men and boys in Srebrenica by the Bosnian Serbs. The overwhelming majority of these victims were buried in mass graves in the remote countryside. The task for investigators following the massacre was not only finding the gravesites, but successfully excavating and identifying the victims.

The UN defines a mass grave as a location containing three or more victims who have died by extra-judicial or arbitrary executions that are not the result of an armed conflict (an extra-judicial action is one that takes place by a state or other official authority without legal process or the permission of a court).

Investigators need to determine not only time since death, but also discover any evidence of torture, the specific method of death, and the identity of the victim where possible. For many bodies, this may be a near impossible task.

Among the numerous challenges confronting researchers during mass grave excavations in Bosnia were:

• State of the remains: Victims were often not buried immediately after death because of the need to bring in heavy equipment to dig the grave. As a result, partially decomposed remains became separated and scattered within a single gravesite. The heavy machinery used to dig mass graves and to transport and bury the dead also caused damage to both the soft tissue and the skeleton, masking original trauma and complicating the investigation.

• Victim collection and labeling: During any forensic recovery, each separate body part is identified as an individual specimen. Any possible personal effects or related body parts must be labeled with related information for later association, leading to an incredibly complex identification scheme.

• Secondary and tertiary graves: A large majority of the mass graves in Bosnia were reopened, and disinterred victims moved to secondary or even tertiary graves. Since this occurred anywhere from one and four months post-mortem, soft tissue degradation was well advanced, leading to significant scattering of victims’ remains across large swathes of countryside.

• Lack of associated physical objects: Bodies were carelessly dumped into mass graves and often tightly packed to keep the site as small as possible. When personal effects were recovered, it was often impossible to determine to whom they belonged.

• Clandestine sites: Mass graves, by design, were purposely situated in difficult-to-identify locations, usually in remote areas. In addition, the killers deliberately tried to make victim ID difficult by having their victims remove all personal effects, such as wallets and jewelry, before execution.

• Sheer number of victims: Some mass graves in Bosnia contained up to 700 victims. This made victim recovery and identification a substantial task simply from a procedural and practical standpoint.

• Need for large international teams: Human rights horrors such as mass graves are very difficult tasks for investigators, frequently leading to depression and fatigue. Regular replacements are required, and the specialized nature of the work involved requires an international effort to staff a large team. It will normally take 1 or 2 investigators approximately 4 days to excavate a single victim. If a grave has hundreds of victims, it can take a team of several dozen investigators months to complete.

• Need for on-site facilities: Due to the remote nature of most mass graves, investigators must build or acquire forensic facilities for their investigation—including refrigerated storage areas, running water, decontamination areas, and sorting areas for both remains and personal effects. Provision must also be made for site security during the excavation, and accommodations for the technical staff.

• Victim identification: The majority of mass grave victims frequently lacked sufficient dental records to allow for dental identification. As a result, pathologists and forensic anthropologists had to rely on physical features and antemortem fractures to establish victim identification.

Next week we’re going to look at the practical side of mass grave excavations—how to find the graves—and then, once they are located, how to recover the victims.

Photo credit: Wikimedia Commons and Gilles Peress.

Forensic Case Files: The Srebrenica Massacre

July 11^th this past week marked the 18^th anniversary of the beginning of the Srebrenica massacre—the day the Bosnian Serb army, under the command of General Ratko Mladić, took control of the UN protected enclave of Srebrenica in Bosnia.  Two days later the genocide began.  Between July 13^th and 22^nd, 1995, over 8,100 Bosnian Muslim men and boys were massacred and buried in mass graves by the Serb Army. Between August and November of 1995, many of those bodies were moved to secondary and tertiary mass graves, scattering remains across 300+ grave sites. The locations of these graves were largely unknown to outside investigators, and while a large number of them have been discovered, many are still unidentified.  Teams of pathologists and forensic anthropologists are sponsored by the International Commission on Missing Persons to excavate each newly discovered grave. Attempts are made to identify remains by PCR, physical characteristics and personal belongings found within the grave.  It is truly horrifying work for the ICMP team members, but it is also rewarding as missing loved ones are finally identified and put to rest.

DNA analysis comparing family member samples to the unidentified remains has resulted in the identification of 6,838 individuals from the more than 8,100 reported missing following those 10 days in July. But there remains no trace of over 1,200 men and boys to this day.

On July 11th of each year, all of the newly identified dead are brought to the Srebrenica Genocide Memorial in Potočari for burial.  Last Thursday, 409 additional sets of remains—often no more than a handful of bones—were laid to rest at the memorial. Included in the dead were 43 boys between the ages of 14 and 18, and a newborn infant who was born during the massacre.  This brings the total number of remains interred here to 6,066.

Next week, as we explore this difficult topic further, we’ll look at the forensic anthropology challenges of mass graves.

Photo credit: green-draped coffins—Almir Dzanovic, mass grave exhumation— Photograph provided courtesy of the ICTY, Potocari gravestones— Michael Büker, Potocari Memorial—Mazbln and Potocari Memorial names— Michael Büker; all Wikimedia Commons

Forensic Case Files: Guatemalan Genocide

Guatemala was once home to an advanced Mayan civilization that flourished from about 250 C.E. to nearly 1000 C.E. Their declining civilization was overrun by the invading Spanish in the 16^th century. Conquered by weapons of modern warfare and devastated by European diseases, the Mayans became the Guatemalan peasant and labouring class to the Spanish upper class. But not even invading Europeans would wreak as much death and destruction as Guatemala’s own government in eighteen months between March 1982 and August 1983.

Coffee production is one of the Guatemala’s main industries and was heavily invested in by Americans during its infancy in the early- to mid-20^th century. Large coffee plantations were run by the white upper class, while the indigenous Mayan population worked the fields. As a result, a large gap formed between the police-protected white populace and impoverished natives.

During the 1940s and into the 1950s, successive governments made great strides in improving conditions for the native populations, but a C.I.A.-facilitated coup in 1954 overthrew the existing government due to the rumoured threat of Communism. A military dictator was installed to lead the country and this became the style of government for the next several decades. During that time, several guerilla factions rose up to threaten the government, leading to the Guatemalan Civil War (1960 – 1996). The government’s response was to deal quickly and violently to any guerilla threat.

In March of 1982, General Efrain Ríos Montt overthrew the government in power and installed himself as President. His views regarding the guerilla resistance were very clear: “If you are with us, we’ll feed you; if not, we’ll kill you.” Officially, he ordered paramilitary ‘death squads’ out into the mountains with the intent of discovering and killing guerilla soldiers.

But something much more tragic took place. Over the course of the next year and a half, 669 massacres occurred at Mayan villages. Death squad soldiers would wait until the village gathered together for a celebration or market day, and then the entire community was targeted under the guise of harboring guerilla rebels. Peasants were shot, stabbed or bludgeoned to death. Many had their limbs amputated. Some were impaled and left to die slowly, or doused with gasoline and set afire. Women and girls were raped, the elderly were slaughtered, babies’ heads were smashed against poles, and children were thrown into mass grave pits of the dead and buried alive. Afterwards, soldiers took or killed the livestock, destroyed crops, fouled the local water supply, and desecrated any sacred places. Then they burnt what was left of the village to the ground. It was true ‘scorched earth’ warfare. Those fortunate enough to flee to the mountains were hunted by soldiers with the goal of exterminating the entire village. Hundreds of thousands of displaced peasants became refugees.

More than 200,000 native Mayans were murdered and another 50,000 ‘disappeared’ during that eighteen month period. The Mayan population refers to this time as the ‘Silent Holocaust’—when villagers were killed simply due to their ethnicity, not because they supported any rebel faction. The government supported their actions with the claim that the Mayan communities had organized, allied with the guerillas, and were working towards a Communist coup.

In 1994, FAFG, the Guatemalan Forensic Anthropology Foundation started out as a small group of forensic anthropologists and scientists dedicated to the goal of uncovering the dead from this atrocity. In 1995, those five scientists began their first exhumation aided by massacre survivors. Currently the group numbers more than ninety and FAFG scientists are considered to be the world’s experts on mass graves. They have assisted in exposing other massacres, such as Srebrenica following the Bosnian War. They work to discover and exhume mass graves, recover human remains, determine the traumatic cause of death, and attempt to ID the victims based on skeletal structure and associated grave goods.

Shortly after the exhumations began, the U.N. investigated the Guatemalan genocide. In 1999, they finally released a report detailing horrific human rights violations by the military as ordered from the highest levels of the Guatemalan government.

In 2009, the National Security Archive presented a report citing President Montt and his military of carrying out genocidal assault against the indigenous Mayan population. Part of their supporting evidence was a ‘death squad diary’, outlining the disappearances, tortures, and executions starting in the summer of 1982 and continuing into 1983.

For the very first time, a previous head of state is on trial by the justice system of his own country for crimes committed within that state. Currently 86 years of age, and decades after his time in office, Efrain Ríos Montt now stands trial. So far, more than 70 witnesses for the prosecution have testified to the atrocities.

Unfortunately, the trial has been plagued by procedural and technical errors. On May 10, 2013, Montt was convicted of ordering the deaths of 1,771 Mayan peasants and sentenced to 80 years in prison.  But on May 20, that ruling was overturned based on ‘illegal proceedings’—Montt had fired his attorneys on April 19^th and was left without a lawyer for a short period of time while the trial proceeded. Guatemala’s constitutional court ruled this past week that the trial should have been halted until Montt had lawyers in place and that all court proceedings must roll back to April 19^th and start again. All witness testimony up to that time will stand, but the final weeks of the trial now must be repeated.

Guatemala stands as the only modern genocide in the Western Hemisphere during the post-World War II era. One can only hope that justice will be done, but it will be a small consolation to the Guatemalan people, many of whom still mourn those lost during the massacres.

Photo credit: Wikimedia Commons

Forensic Case Files: 9/11—Part 3: Challenges in Naming the Dead

Over the past two weeks, we’ve discussed the tragedy of the 9/11 terror attacks from a forensic perspective—how recovery teams worked tirelessly to collect the victim remains once all hope of rescue was exhausted, and how victim identification is established. Sadly, a full 40% of victims from the World Trade Center are still unidentified. Hundreds of thousands of man-hours have gone into the effort, so why has the process of naming the dead proved so difficult?

There were many problems associated with victim identification, especially in the years immediately following the tragedy, including:

• The sheer number of samples needing to be identified and the amount of data they produced: It is the duty of the Medical Examiner and his staff to identify the dead and issue death certificates. That duty doesn’t change simply because of an overwhelming death toll; each individual still deserves to be named. But because of the nature of death, many victims’ bodies were fragmented, leading to multiple samples from the same individual. Fragmented remains found in the same location may or may not originate from a single victim, so each had to be sampled and analyzed separately. Additionally, personal effects found loosely associated with human remains might not belong to that person, so DNA samples had to be taken from all items. While mass-casualty disasters are not uncommon, the data processing requirements for managing such a large database stretched the technology available to individual laboratories of the time.

• The size and condition of the samples: Due to the harsh conditions of the site, many samples were so badly degraded that DNA typing wasn’t possible. When samples were found five years after the attack on the roof of the Deutsche Bank Building, most of the bone fragments were less than one sixteenth of an inch in size, minimizing the chances of successful DNA extraction.

• Weathering/scavenging of samples found years after the tragedy: The Deutsche Bank Building fragments, for example, were subject to years of freezing in winter, and heat and direct sun in summer for five years. Remains in the lower levels of the World Trade Center, among the last to be excavated, were subject to water, fire, crushing, and toxic waste. Remains in the pile sent to Fresh Kills were subject to scavenging by carnivores, birds and insects.

• Location of the remains: The final resting place of the remains could not be used towards a definitive identification. It might, however, suggest a potential localization—bodies from upper floors may be likely to be less damaged due to the lighter load above them, and fire damaged bodies are more likely to originate from floors near the original crash sites and the ensuing fuel-amplified fire. Additionally, co-mingled remains might be thought to originate from similar areas of the building, if not the same area.

In the years since 9/11, a definitive ID for each victim has proven to be impossible, no matter how much effort has was applied to the task. In the end, at the request of families, 1,616 death certificates were issued without confirmatory identification.

The ultimate question in mass casualty disasters is: when is the project finished? When every victim is identified or when every sample of remains is tested? Sadly, with only 1,119 of 2,753 victims identified, the task of identifying the victims of 9/11 may never officially be complete.

In memory of those lost on 9/11. We will never forget…

Photo credit: WikimediaCommons – U.S. Navy, Wikimedia Commons - U.S. Air Force and Morgan.Davis

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Forensic Case Files: 9/11—Part 2: Identifying Human Remains

Comparison points of ridge characteristics for fingerprint analysis.

Last week, we talked about the challenges of handing a mass fatality disaster such as 9/11, including the collection of human remains. This week, we’ll cover how those remains can lead to victim identification.

The path toward identification starts with the type of sample recovered. When the body is intact, presumptive identification can be made via visual ID or by directly associated personal effects (i.e. a driver’s license with matching photo found in the pocket of the victim). Confirmatory identification can then be made using one of several methods, including DNA matching, odontology or fingerprinting.

Sadly, considering the nature of the 9/11 attack on the World Trade Center (WTC), the overwhelming majority of remains could not be identified so easily. Officially, the New York Medical Examiner lists all of the deaths at WTC that day as ‘homicide due to blunt force trauma.’ This includes those who died in the collapse of the towers, as well as those that fell or jumped to their deaths after being driven out by flame and smoke (these deaths are not classified as suicides since they were not considered voluntary acts).

Because forensic anthropologists specialize in fragmented, burned, decomposed, and comingled remains, they are at the forefront working on victim identification. Well-known author Dr. Kathy Reichs was one of many forensic anthropologists who took time away from their own professional careers to help identify remains found at Ground Zero following the attacks.

For most victims, since only fragments of their bodies were recovered, identification had to be inferred from one or more of the following attributes:

• Personal surface markers like scars or tattoos.

• Forensic anthropologists’ estimate of age at time of death, race, sex, and stature.

• Description of antemortem (before death) characteristics, including evidence of disease or healed fractures.

• Discovery of prosthetics or surgical hardware (including serial numbers).

• Documentation of perimortem (at the time of death) trauma supporting cause of death.

• Fingerprint examination: Qualified personnel can collect antemortem latent prints from the homes or personal effects of suspected victims for comparison to recovered remains. Once identification is made, a second qualified examiner must confirm the match.

• Odontology: Comparison of recovered dental fragments to antemortem dental x-rays and charts. These matches can be difficult because dental remains may be fragmented; extremely fragile dental remains may require onsite radiography before transportation to morgue.

• Radiology: Comparison of antemortem x-rays to post-mortem (after death) x-rays and skeletal fragments in order to match healed fractures.

• DNA comparisons: DNA remains the best method of identification, especially when other physical traits such as fingerprints, physical stature, distinctive characteristics and dental features have been destroyed. The challenge in DNA matching can lie in finding a reference sample for comparison. More detailed information on the subject can be found in one of our earlier posts: Forensics 101: DNA Profiling for Identification.

In a perfect world, every victim would be identified, finally bringing closure to the families. But the task of identifying the victims at the WTC has proven to be extremely difficult in many cases. Join us next week as we close our series on 9/11 as we explore the challenges investigators have faced in trying to put names to the dead.

Photo credit: Vince Alongi

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Forensic Case Files: 9/11—Part 1: Mass Fatality Incidents

The events of September 11, 2001 will forever remain a watershed moment in history—life before vesus life after that day. For North Americans, it marked the end of a more relaxed way of life and the beginning of heightened security and wariness of the world around us.  For most of us, it’s an event, like Kennedy’s assassination, that will forever be linked to what we were doing at the moment we heard the news.

In the past, Ann and I have considered looking at the recovery efforts assocated with the disaster because forensic anthropology remains a crucial part of victim identification to this day. But, at the same time, we’re very sensitive to the fact that this incident remains a very painful moment in time not just for Americans, but for the world as a whole since sixty other countries also lost citizens in the attack that day. Over the next few weeks, we’re going to be looking at the incident from the perspective of managing a mass casualty and fatality incident of this magnitude, and continuing efforts at individual victim identification.

When the planes struck the two towers, significant damage was initially localized to seven or eight stories adjacent to the point of impact, caused by explosion, fire from the heavy load of airplane fuel, and the large size of the modern Boeing 767. The buildings’ collapse was initiated by the weakening and finally buckling structural systems due to the heat of the fire and the crushing static weight of the floors above. The South tower, the second hit, was actually the first to collapse because the plane struck a lower floor, resulting in greater weight above the site of impact.

The sheer volume of calls overloaded communications systems, making it difficult to contact those inside the buildings, including first responders. As a result, many in the North Tower were never aware that the South Tower had fallen, even though nearly thirty minutes passed before the North Tower itself collapsed. 2,753 people, including the passengers and crew of American Airlines Flight 11 and United Airlines Flight 175, perished in the tragedy.

The initial response was search and rescue in an attempt to recover anyone who might have survived the crushing collapse of either building. The instability of both the immediate scene and the surrounding buildings hampered rescue attempts and teams were called off repeatedly as concerns about the collapse of nearby buildings heightened; 7 World Trade Center collapsed later that afternoon as a result of the fires that started after the building was hit by debris from the North Tower. Only when the scene was stabilized were rescue workers allowed to return. Multiple hazards were also a concern throughout this phase, including an underground tank of diesel fuel, gasoline from several thousand cars buried in the underground parking lots, and 1.2 million rounds of ammunition in the U.S. Customs Service firing range on site. Sadly, in the days following the attack, only 11 survivors were pulled from the rubble. Some victims survived the collapse of the towers but rescue teams were unable to reach them in time.

Recovery teams formed bucket brigades, passing five-gallon buckets down lines to investigators who sifted through each to remove any evidence of human remains. ‘The Pile’ was then transferred to one of several landfill sites, including Fresh Kills on Staten Island. There, the debris was sorted once again, and any additional human remains and personal effects were collected. The majority of remains collected were recovered during the ten months following September 2001.

Salem Fire Department’s 9/11 memorial, including a steel girder from one of the towers.The New York City Office of Emergency Management was in charge of the recovery and cleanup. Keenly aware of the effect on the city of the specter of the wreck of the World Trade Center, they attempted to clean up the 130,000 tons of debris as quickly as possible. Inadvertently, this rapid cleanup caused some remains to be separated from personal effects which could be used to aid in victim identification, and further scattered the remains of dismembered bodies. Inadvertently, human remains may have been disturbed as remains and comingled effects became separated, or as associated remains became scattered. In 2005, the search was declared complete despite concerns raised by families of those still missing that the initial efforts had been too rushed or carelessly handled. But after the discovery of bone fragments on the roof of the nearby Deutsche Bank Building and in two manholes in 2006, a new investigation was launched and 1,500 additional remains were recovered.

Twelve years after the attack, the cleanup process continues. In just the last few years, over sixty truckloads of debris have been removed from the site. On April 1, 2013 two more skeletal fragments were discovered. Currently, 40% of the victims are still unidentified, so efforts to identify the missing and the dead will continue.

Next week, we’ll look at identification methods used following the attacks to identify the dead.

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Forensics 101: Bullet Wounds in Bone—The Skull

In a previous Forensics 101 post, we looked at how kerfs—the grooves and notches made by tools on bone—can help scientists identify the method of death in a murder investigation. But the rise of gun crime in North America has made the forensics of wound ballistics increasingly important. There are two different types of damage in this kind of wound—soft tissue and bone. In this post we’re going to strictly look at bone damage, concentrating on the skull and its very characteristic fracture patterns.

Unlike blunt force trauma, gunshot wounds often cause both an entrance and an exit wound. Investigators need to be familiar with how bone behaves in both circumstances to reconstruct the order of events and be able to piece together the details of the fatal shot. Different variables that affect the type of damage done to the bone include the velocity of the bullet (which depends on the type of gun used and the distance between the shooter and the victim), the size/caliber of the bullet, and the angle of impact.

If a bullet penetrates the skull perpendicular to the surface, a round defect is formed, often with outward radiating fractures extending from the bullet hole. The force of the bullet’s entrance increases the intracranial pressure inside the skull, causing the pieces of bone between the radiating fractures to push outwards. These ‘heaving fractures’ can be differentiated from blunt force trauma fractures because the bone sits above the plane of the skull instead of below it. The energy transfer from the bullet to the bone can be so efficient that the radiating fractures can travel through the bone to the far side of the skull faster than the bullet can traverse the brain and exit. This fact can be crucial in determining the order of fractures since a new exit fracture cannot cross an existing entrance fracture.

When a bullet strikes the skull tangentially, a characteristic ‘keyhole’ is formed—a defect that is circular at one end with tangential fractures radiating outwards in parallel, allowing the bone between them to lever out.

Exit wounds often tend to be much larger than entrance wounds for a number of reasons: the bullet is misshapen or ‘mushroomed’ from the initial bone strike, the bullet may no longer be moving along a straight trajectory, or the projectile may be tumbling end-over-end. Often large chunks of bone may be completely detached from the skull following the bullet’s exit. Sometimes, however, the bullet’s energy is spent following the initial strike; when this occurs, the bullet does not exit the skull and can be recovered later during autopsy.

Contrary to popular belief, the size of the bullet wound does not directly correlate to an exact bullet caliber because factors such as bullet shape, jacket material, stability of the bullet’s flight path and whether any other targets have been hit tangentially can affect the force with which the bullet strikes the bone.

Photo credit: Ann H. Ross, The University of Tennessee and Gérald Quatrehomme et al, Florida Atlantic University

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Forensics 101: Using the Bomb Curve to Date Human Remains

Over the past month, we’ve discussed human remains that were centuries—King Richard III—if not a millennium old—King Alfred the Great. For remains of this age, classic carbon dating is the most reliable way of determining time since death. But is there a more precise way to date more recent remains, remains that might only be thirty to fifty years old, instead of six hundred? There is, and that method uses the fallout from nuclear testing following the Second World War to determine time since death.

Following the end of the Second World War, nuclear weapons were tested by the United States, the United Kingdom and Russia. The fallout from this testing radically changed the percentage of radioactive carbon—14C—in the atmosphere, spiking significantly in the early 1960’s before peaking in 1963 at a level nearly twice that of 1950. Atmospheric 14C levels fell slowly in the decades following, but still remain 15% higher than in 1950.

Average atmospheric 14CO2 for the northern hemisphere

Just as strontium is incorporated into living organisms, 14C in atmospheric CO2 enters the food chain when plants use it to manufacture carbohydrates and proteins during photosynthesis. Those plants are then eaten by herbivores and become a permanent part of that animal’s bone structure. As a result, 14C from samples taken from skeletal remains after the 1950’s can be compared to the bomb curve to determine relevant dates. Samples taken from the mid-shaft of long bones represent childhood 14C levels. Spongy cancellous bone sampled from the ends of long bones will show a greater amount of turnover and remodeling that correlates closely to the date of death. Enamel from teeth captures a snapshot of the time when the tooth developed and erupted. If all the values fall in the pre-1950’s range, a different manner of aging the remains must to be used. But for those values that fall post 1950, a window of only a few years can be determined for the date of death.

The slow drop in atmospheric 14CO2 following the early 1960s is due to the signing of the Limited Test Ban Treaty. In August of 1963, representatives from the United States, Russia and the United Kingdom signed a treaty banning all nuclear testing in the atmosphere, in space or under water. In the decades that followed, 123 additional countries signed the ban (the most recent was Montenegro in 2006), leaving 58 states as non-signatory.

Photo credit: Fastfission via Wikimedia Commons and Ubelaker, DH et al. Analysis of Artificial Radiocarbon in Different Skeletal and Dental Tissue Types to Evaluate Date of Death. Journal of Forensic Sciences; May, 2006

Giveaways!

A new Goodreads giveaway starts today! I’m giving away an autographed ARC to Canadian entrants. The contest closes on March 15, 2013: http://www.goodreads.com/giveaway/show/46552-dead-without-a-stone-to-tell-it

Five Star is giving away 10 copies to American entrants, ending on March 25, 2013: http://www.goodreads.com/giveaway/show/41803-dead-without-a-stone-to-tell-it

A Facebook giveaway! Stop by Facebook for your chance to enter a Rafflecopter giveaway for a chance to win an autographed ARC: http://is.gd/iDxH1z