Forensic Case Files: 9/11—Postlude

First of all, for those that might not have seen the news, we’re now officially contracted once again with Five Star. The second full length book in our Abbot and Lowell forensic mystery series—A FLAME IN THE WIND OF DEATH—is scheduled to release in early May, 2014.

And now, onto this week’s blog post…

Over the past three weeks, we’ve covered the 9/11 World Trade Center tragedy from a forensics point of view—how to handle a mass fatality, how to identify human remains following such an incident, and the challenges investigators have faced in identifying the dead from that day. We thought the series was complete with those three posts until last Friday when a news story broke, reporting on a piece of a Boeing 767 found three blocks from the World Trade Center. Originally thought to be part of the landing gear assembly, it is, in fact, the trailing edge flap support structure in the wing. The 5’ x 3’ x 17” piece was wedged into the 18” gap between a loft apartment building and a Muslim mosque, behind a gate, out of sight from the sidewalk, ensuring it remained undiscovered.

It was a stark reminder that even though September 11 happened nearly 12 years ago, it remains relevant to this day and the search is far from over.

The part was found purely by chance—a building inspector was on the roof and spotted it between the buildings from above. He called 911 and the NYPD responded, immediately cordoning off the area and later designating it as a crime scene. Police will investigate to ensure the piece wasn’t placed there deliberately, and the Medical Examiner’s office will do a toxicity screen and then determine if any human remains are associated with the site. Despite an identification number stenciled into the metal, Boeing has stated that it cannot trace where the piece originated.

The real question is how did the part get there? Because of the rope wound around one end of the piece, police are investigating whether it could have been lowered down into the gap. But what would be the intent behind such an act? Assuming the part did indeed come from one of the two doomed aircraft (not many people would be able to obtain parts from a 767, after all), it landed in that area eleven and a half years ago. It is possible that someone found the piece on the roof and then attempted to hide it between the buildings, but it would be a futile act considering all the other airplane debris in the area. If it was placed there in hopes of being found more quickly, then the wrong area was picked as it lay unnoticed for over a decade. If a recovery team had attempted to lift if from the roof and accidentally dropped it between the buildings, it would have been reported at the time. Conspiracy theorists may try to come up with alternative ideas, but what makes the most sense is the initial conclusion the inspector and most others came to—the piece landed there following the crash that fateful day.

It’s true that the statistical odds of the piece hitting in the exact orientation to fall between the two buildings and not bounce to an adjacent roof is extremely small. In fact, a piece of the landing gear went through the roof of the building next door to this current site. So while it’s hard to fathom the chances of a piece of that size landing as neatly as it did, it’s not impossible. Based on data included in a 2002 FEMA report (see the illustration to the right), this new evidence was discovered very near the ‘landing gear’ on the lower right of the diagram which came from United Airlines Flight 175 after it hit the south tower. It’s most likely that this piece also came from the same plane, simply from a physics standpoint of mass, velocity and inertia.

More details will be released as they come to light, but families of survivors are now calling for a full search of lower Manhattan to ensure that no other parts or remains stay undiscovered. Each time a new discovery is made, it pulls the families of the lost back into the past, opening old wounds. If there is any hope of moving on, all remains and debris must be recovered. The dead will not be forgotten, but we owe it to them and their families to finally lay them to rest.

Photo credit: New York Police Department and FEMA

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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