Experts examine 14,994 remains to try to identify the 9/11 dead. In
the process, they are reinventing a science.
Robert Lee Hotz, Los Angeles Times
The human remains of the day shelter in the shade of a white tent
near the East River's edge.
Here, set off by wilted bouquets, are the unanswered questions of the
World Trade Center dead, stored in the 16 refrigerated trailer trucks
parked on this shaded sliver of vacant pavement.
Each question is an anonymous flake of human bone or fleck of flesh
picked from the rubble and preserved in a scientific limbo. There are
14,994 of them.
This is death divorced from identity--body parts without names to
claim them; names without remains that can be mourned.
These human fragments are the dark heart of an unconventional murder
mystery that will take years to solve. There is no question who
committed the Sept. 11 attack or why terrorists may have acted as
they did; little question now of the 2,797 names of those who died.
The only answer authorities still seek--at a cost of $ 58 million
since last fall--is how to settle those names on these unidentified
Only half the dead have been identified so far.
The search has brought investigators to the edge of what science can
discern of death.
By necessity, forensic specialists led by Dr. Robert Shaler, head of
forensic biology at the New York chief medical examiner's office, are
virtually reinventing the science of identification.
Their pursuit of identity has turned the busiest morgue in the U.S.
into a laboratory at the forefront of human gene research. They are
forging the new tools of 21st century forensic medicine.
They are creating better ways of handling DNA, perfecting new genetic
testing techniques and developing computer programs to analyze
genetic variations. The new techniques one day may help diagnose
inherited traits across the entire human population.
"We are moving into new territory," Shaler said. "I feel as nervous
as I did the first day of the attack."
In its scale and scientific demands, the federally financed World
Trade Center investigation is unique in the annals of crime and
forensic medicine, experts say.
In an effort that rivals the Human Genome Project, Shaler has
marshaled a national network that includes the New York State Police,
the FBI, six biotechnology companies, a score of DNA consultants,
computer software developers and an advisory committee of 30 forensic
experts that has met every eight weeks to thrash out technical issues.
So crushed, burned, waterlogged and corroded are these remains that
they defy conventional identification techniques, forensic
specialists quickly discovered.
Consequently, almost half of the identifications made so far have
been solely on the basis of genetic testing--682 of the 1,411
named--and DNA analysis helped in the identification of 343.
Of the rest, there is not enough undamaged DNA to build a normal
Even now, no one can even tell how many people these refrigerated
tissues encompass. No one knows how many people vaporized in the
fiery crashes and collapsing towers.
The fires took three months to extinguish. Crews sifted 1.6 million
tons of debris for nine months to exhume the remains.
Death crushed some people so fiercely that only genetic analysis has
been able to tell their intermingled cells apart.
Death made a jigsaw of others. More than 180 pieces of one victim
have been identified so far. The slayers and the slain mingle, flesh
and bone, in an autopsy test tube.
The forensic experts so far have matched 4,930 body pieces to 1,411
of the victims and given over many of them for burial or cremation.
"If this had occurred in 1980, or even 1990, the forensic work would
have to stop now, with only half the people identified after heroic,
intensive work," said Clyde Snow, a forensic anthropologist who
helped pioneer modern identification techniques.
By pushing the state of the forensic art, Shaler is hoping to
identify remains of at least 600 more victims.
In recent weeks, the forensic experts have invented more refined
testing techniques to extract usable DNA. They are retesting every
one of the thousands of unclaimed pieces of bone, flesh, hair and
clotted blood samples.
Conventional genetic testing--the mainstay of the effort so far--is
reaching its limits. Shaler is resorting to experimental genetic
techniques never before used on such a scale.
Since June, DNA experts at Celera Genomics in Rockville, Md., have
processed 19,000 DNA specimens from victims and relatives, examining
the genetic material contained in the thousands of mitochondria in
The DNA in these cellular power plants is inherited directly from
each person's mother. It is much smaller than DNA found in the
nucleus of a cell but is much tougher and more likely to survive
intact in damaged tissue.
This month, forensic experts at Orchid Cellmark Inc. in Germantown,
Md., expect to begin tests that look for single variations in the 3
billion characters of the human genome. These differences--called
single nucleotide polymorphisms--are part of the reason every
individual is unique. So far, scientists have mapped 1.4 million of
these molecular variations in humankind.
Forensic experts are contemplating more exotic methods that might
allow them to rebuild shattered fragments of DNA the way a cosmetic
surgeon can rebuild a face.
Even for those professionally hardened to death, the work is
It is not uncommon to find forensic technicians weeping at their
computer terminals. Several have asked for transfers. One lab expert
quit under the strain earlier this year. A second broke down
emotionally and was hospitalized.
There is no room for error. Perfection is the acceptable legal standard.
Even so, they must anticipate failure.
Morgue technicians already are drying these tissues, like petals of
rare flowers, to preserve them for a day when more advanced
technology may allow the identification of the most damaged remains
"If somebody wants to look at this 20 years from now, they will be
able to scrutinize it," Shaler said. "Somebody, someday will
challenge what we have done."
When the first hijacked airliner hit the World Trade Center, Shaler
was holding his regular Tuesday morning staff meeting to plan the
workload for the 90 forensic experts under his direction.
Shaler, 59, has unblinking blue eyes shielded by frameless glasses. A
closely trimmed white beard softens his expression. He is light on
his feet as he sidesteps the cardboard boxes of unfinished cases that
crowd his office cubicle.
In more ways than one, Shaler is married to his work. His wife, whom
he met at a medical examiners conference, is a forensic scientist for
the New Jersey State Police.
After almost 14 years in the medical examiner's office, he is no
stranger to the confusion that fogs the circumstances of violent
The city's Office of the Chief Medical Examiner, led by Dr. Charles
Hirsch, is the country's busiest, handling 25,000 deaths a year,
including 3,300 homicides and sexual assaults. Hirsch recruited
Shaler to found the forensic biology laboratory.
As conflicting reports filtered back to the medical examiner's office
on Sept. 11, a seven-member emergency morgue team mobilized and
headed downtown, in accordance with the city's long-standing plans
for any air disaster.
It was no surprise when they left without asking anyone from the
forensic DNA team to go with them. They were never included in
Within hours, the sobering scale of the World Trade Center disaster
emerged. Early reports placed the dead at 6,700 or more. Morgue
experts were braced to handle as many as a million body parts. The
numbers of the missing and murdered continued to fluctuate for months.
In all, they would find 19,924 body parts.
For nine months, human remains recovered from the Trade Center site
or culled from rubble trucked to the Fresh Kills landfill on Staten
Island were delivered to the open-air bay by the side entrance of the
medical examiner's office. Even now, tissue still turns up. The most
recent fragment was delivered from the World Trade Center area Monday.
There, under a canopy on a cul-de-sac blockaded by six metal
barricades and under police guard, Shaler and his staff took
possession of the dead.
As the only full-time forensic anthropologist on the medical
examiner's staff, Amy Zelson Mundorff was the first to examine
remains when they came through the door, the last one to sign them
out when they finally were identified.
Pathologists, dental experts and fingerprint analysts searched each
new set of remains for identifying marks or features that might help
distinguish it from the other dead--a distinctive tattoo, a pattern
of freckles, a healed bone fracture, a birthmark, a wedding ring.
Each piece was cataloged, tagged with a bar code and measured.
"We would go through the bags and sort out the cases," Mundorff said.
"Anything that was not attached to something else got its own case
number. We would take the time, if we could, to put the pieces back
together, if we could make it into one case."
She kept at it 12 hours a day, six days a week.
For many emergency workers, the difference between the quick and the
dead at the World Trade Center was uncomfortably close.
On that Tuesday morning, Mundorff had rushed to the World Trade
Center shortly after the first aircraft crashed into the building, as
part of the disaster team dispatched to assess the scene.
Pressing forward with other emergency workers, she was caught in the
tumbling outwash of debris from the fall of the south tower. Slammed
against a wall, she suffered a concussion and broken ribs. Rubble and
broken glass slashed her legs. One of her co-workers fractured his
For the first month, she looked at sets of remains through two blackened
"We were too close," she said. "When I look at the cases on the
table, I feel lucky."
As Mundorff and her colleagues sorted through bag after bag, it
became clear that the mainstays of forensic identification--detailed
skeletal analysis, dental X-rays and comparison with existing medical
records--were all but useless.
There rarely was enough bone to make a recognizable skeleton; no
faces that could be reconstructed; few teeth to be matched to dental
records; even fewer whole fingers to print.
"So many of our traditional anthropological techniques are obsolete
in a mass disaster like this," Mundorff said. "It is frustrating. We
have to take what we know and apply it in a different way."
Of the 2,797 dead, only 287 whole bodies were found. Only 185 people
could be identified solely from their teeth; 70 from their
By contrast, remains of the 44 people who died in the crash of United
Airlines Flight 93 near Shanksville, Pa., were all quickly
identified, aided by accurate passenger manifest information.
All but five of the 189 people who died at the Pentagon have been
identified. Forensic experts were able to take advantage of military
identification tags and extensive government medical files.
Remains of nine hijackers from those two crash sites also have been identified.
But the victims of the World Trade Center attack included office
workers and visitors from 60 countries, shredded now beyond all
To identify the fragments, the medical examiner's technicians would
have to look deep into the heart of the human cell.
Properly treated, the nucleus of a cell can yield the long, twisted
thread of DNA that forms the unique molecular signature for every
individual. Stretched to its full length, that strand of DNA is
almost 6 feet long. It weighs barely a billionth of a gram.
Only one-tenth of a single percent of DNA differs from one person to the
Scientists can use these variable regions to generate a DNA profile
of an individual, using samples from blood, bone, hair and other body
tissues. In conventional genetic testing, a series of chemical probes
will bind to the DNA sample in a distinctive pattern for an
That, in turn, can be compared to DNA from the victim's personal
effects or with that of relatives.
Robotic gene sequencers and supercomputer bioinformatics systems
would have to do what family and loved ones could not.
"We take snippets of tissue--less than a cubic centimeter," Shaler
said. "It is not much, but there are tons of cells in there. You just
need to find 100 good cells."
It is technology whose time had come.
By last year, 120 DNA crime laboratories were involved in more than
16,000 cases and were analyzing more than 265,000 samples from
convicted offenders. In New York alone, genetic testing is being used
to reevaluate evidence in 17,000 unsolved rapes.
As a new tool of mass identification, genetic testing helped
investigators identify all 230 of the victims of TWA Flight 800,
which crashed in the ocean off Long Island in 1996. It helped
resurrect the identities of the murdered from the mass graves of
Bosnia and Guatemala. It reunited families with remains of
long-missing soldiers killed in Korea and Vietnam.
In the process, genetic testing also altered public expectations
about the anonymity of death. With so much scientific knowledge to be
had from the code of life, a nameless death seemed an affront.
Even America's Unknown Soldier was no longer unknown.
In 1998, the remains of an unidentified American serviceman from the
Vietnam War, buried beneath the Tomb of the Unknowns in Arlington
National Cemetery, was removed from his public tomb, identified
through genetic testing and returned to his family.
The crypt has since remained vacant.
Just as genetic testing altered the forensic science of
identification, however, the demands of the World Trade Center dead
would in turn change the technology of genetic testing.
As a laboratory technique, modern genetics depends on highly
automated machinery that can perform the mindless, repetitive
chemical work of gene sequencing at high speed, running as many as
800,000 genotypes a day.
Scientists around the world dump more than 100 million bases each
week into a public data repository. It takes arrays of supercomputers
to make sense of the raw genetic sequences, by identifying the
patterns of DNA code that indicate genes or the presence of
Although New York City has the largest forensic DNA lab in the
country, the demands of the World Trade Center investigation
instantly swamped its resources.
The medical examiner quickly drafted the New York State Police
forensic DNA laboratory in Albany and two of the world's largest
genetic sequencing companies: Myriad Genetic Laboratories Inc. in
Salt Lake City and Celera Genomics, which was the first private
company to sequence the human genome. A third company, Applied
Biosystems Inc. in Foster City, Calif., provided equipment and
Two of the most experienced private forensic DNA identity
laboratories--Orchid Cellmark and the Bode Technology Group in
Springfield, Va.--also joined the investigation.
Laboratory Corp. of America, which has 900 DNA centers around the
country, and the New York State Police collected almost 7,000 razor
blades, combs, toothbrushes, lipsticks and other items that had
belonged to victims, which could be tested for DNA and compared to
remains. From relatives, they also collected more than 6,800 DNA swab
samples to be compared with victims' genetic profiles.
Soon, couriers were crisscrossing the country carrying sealed pouches
full of bar-coded vials of DNA.
But no one had ever tried to use these high-speed laboratory DNA
extractors and gene sequencers to handle so many tissue samples so
Nor were research laboratories accustomed to the unforgiving demands
of forensic identification or the legal niceties of handling evidence.
From the outset, it was more than the robots and the prepackaged
biochemical kits could handle.
Shaler's technicians processed the first 3,000 sets of remains by
hand, extracting the DNA themselves.
The chemical extraction solutions had to be customized by trial and
error, the timing adjusted and procedures revamped. As the weeks went
on, every one of the processing methods was customized to handle
these unusual human cells, said Brian Ward, president of operations
Scientists were retrained. Laboratories were rebuilt and secure
evidence rooms constructed to hold the DNA. The reliability of new
procedures was tested again and again, then certified by the New York
Department of Health.
At Celera the new labs were ready by November, but it took until June
to develop computer programs that could analyze all the data the
high-speed sequencers spit out.
"There has never been a laboratory using high-speed robotics to
process such a large number of mitochondrial samples--not the FBI,
not the Defense Department, not anywhere," said Rhonda Roby, forensic
manager for Applied Biosystems.
Almost 20,000 DNA samples were sent to Myriad for analysis on its 12
high-speed sequencing robots.
More than 13,000 bone samples were shipped out for testing and
analysis to the Bode laboratory. So were DNA extracts from 4,000
remains and 3,000 DNA samples gathered from family members or
"The bones are the hardest to do," said Tom Bode, general manager of
Bode Technology Group. "Most of them have been subjected to 2,000
degrees Fahrenheit for weeks on end."
The pressure of so many dead pushed the company's workers and
technology to new extremes.
When Alaska Airlines Flight 261 crashed two years ago off the Ventura
County coast, it took the Bode laboratory three months to process DNA
from 860 bones recovered from the ocean, then considered a record
By comparison, the lab processed 2,000 bone fragments from the World
Trade Center dead in one week last October. Working around the clock,
they continued to process 1,000 new samples a week for the rest of
As the weeks turned into months, however, only half the remains
yielded useful DNA. Almost one-fourth showed no DNA at all.
Shaler soon realized that technicians would have to test all the
unclaimed remains again, in the hope that they had learned enough
from the year to coax a name from even these damaged cells.
In the DNA identification room, Shaler squinted at the matrix of the
dead scrolling across the computer monitor.
Each numbered cluster of items detailed a set of body pieces,
personal effects and DNA from families of victims that all have a
genetic sequence in common.
Shaler clicked on a case number with the computer mouse.
The microprocessors brooded briefly, then flagged one collection of
remains with a yellow tag.
"This looks like a potential mix-up," Shaler said.
Retesting revealed that two people--a man and a woman--had died in
the same spot, their remains intermingled in the crush of tons of
falling Trade Center rubble. The tissues were recovered by rescue
workers and collected in a single 50-milliliter test tube. Muscle
clung to bone.
"People died together," Shaler said. "We have a lot of that."
Down the hall, three industrial freezers were stocked with vials of
World Trade Center DNA. Nearby, a walk-in chiller held a roomful of
bones gleaned from the rubble. Red plastic containers holding
personal effects of disaster victims were stacked six deep to the
On Shaler's computer display, it was all reduced to symbols: life
code and computer code.
In this molecular search-and- rescue effort, they are aided by a
sophisticated computer matching program developed during the course
of the investigation by an Ann Arbor, Mich., company called Gene
The program can cross-match thousands of gene sequences at a keystroke.
"DNA is the sexy part, but the real underpinning of all this is
computer software," Shaler said. "Without this, it would be
Shaler moved the computer cursor down the ranks of the dead.
He clicked on a case number.
The screen blossomed into a matrix of genetic sequences from 63 body
parts, matched against the DNA extracted from the bristles of a
toothbrush brought in by a victim's family.
"They all match this one person," Shaler said. "And we have the
Even so, the computer's conclusion must be independently confirmed by
a second set of genetic tests, then laboriously cross-checked against
all the family records and personal effects on file, to make sure
that no one puts the right name to the wrong body.
"Even if you were 99% perfect, you would have still misidentified 28
people," said Mike Hennessey, project leader for the World Trade
Center identification system.
The heart of the system is the program developed by Gene Code
Forensics. With 96,000 lines of code, the software links every item
in the investigation, information once scattered through 22 different
databases and countless file cabinets at laboratories in five states.
With it, Shaler and his forensic team can simultaneously sort in
seconds information from three different types of DNA tests on almost
20,000 partial human remains and compare it to more than 3,000 DNA
samples gleaned from cheek swabs of victims' kin and genetic material
taken from almost 8,000 personal effects.
Other computer programs allow morgue analysts to cross-check family
relationships and calculate the statistical probabilities of a match
between genetic samples and family groups.
In some cases, Shaler and his team have been able to use the computer
programs to meld partial fragments of DNA from different but related
samples, to create virtual genetic profiles for comparison purposes.
The company delivered the first version of the program, called the
Mass Fatality Identification System, in December.
It made 55 conclusive identifications its first day. Now the team
revises it every week to handle the changing demands of the
"This requires a level of quality assurance beyond anything we have
ever done, because of the consequences of a mistake and the emotional
pressure," said Howard Cash, the president of Gene Code Forensics.
"Nothing can ever be wrong."
Every Friday morning, Cash flies from Michigan to New York,
hand-carrying the latest update of the software.
When he walks through the lobby of the medical examiner's office, he
passes a child's note taped to the wall, written in red crayon on
white construction paper: "I hope you find the people."
The dead transform the landscape they occupy, even as a temporary measure.
In this way, a cornfield becomes a battlefield monument. A stretch of
invasion beach becomes a place in the heart.
So too this sloping asphalt slab where the homeless dead are parked
has--without planning or public ceremony--become a memorial.
There is no plaque.
There is the smell of the dead, the steady hum of cooling fans and
the roar of the rush-hour traffic on FDR Drive beyond the barbed-wire
By the morgue tent, three unpainted plywood walls have been erected
to give visiting families an easel to write their thoughts of love
and remembrance. An architect is at work on drawings for a temporary
Along the walls, mourners taped up a photograph of the wife, the
husband, the father, the mother, the son, the daughter, the friend
whose remains have yet to be identified and released.
Every Friday afternoon, Charles Flood, an Episcopal chaplain from
Philadelphia, lights a single candle by the morgue tent and holds a
prayer service. He reads aloud the 23rd Psalm, should any among the
living be there to listen.
"This DNA process is all wrapped up in feelings of wanting to conquer
death," Flood said. "It is very American. It is a way of saying we
will prevail: This dust shall have a name again."
Some families cannot bring themselves to come. A few cannot stay away.
There is a woman who comes every day and leaves one fresh flower. A
couple from New Jersey paid their first visit not so many evenings
Their son is here. They know the trailer where his remains are
stored. More of him may yet be identified. They agonized over how
much longer to wait before holding his funeral.
They left his picture by the trailer.