Restoring Identities to Victims

Identity--the first thing each infant learns--is the first thing death erases, leaving the body a riddle that only a name can resolve.

With a name, a family can bury a loved one. With a name, an estate can be settled; a headstone can be etched; an end can be made.

Restoring the proper name to each scrap of bone and flesh found in the rubble of the Sept. 11 attacks on the World Trade Center here is expected to require what experts in the field say will be the largest forensic identification effort ever conducted in this country. So crushing was the collapse of the twin 110-story towers, so caustic the chemicals unleashed, and so fierce the fires, that few intact bodies are being found.

Since the attacks, scores of medical examiners, dental experts, molecular biologists and pathologists at laboratories in New York, Utah and Maryland have been struggling to identify the remains.

In the end, a million fragments of human body parts--many burned or torn beyond recognition--may be found in the wreckage, several forensic experts said. Each fragment will be bagged, tagged with a bar code, entered into a computer database, and its every characteristic--down to its DNA--studied intently in the months to come.

There are other teams studying the remains of those who died at the Pentagon in Virginia and in the crash of United Airlines Flight 93 near Shanksville, Pa. But the problems facing forensic experts in New York are especially daunting.

The Pentagon has military identification tags and DNA banks to assist in identifying victims. Airlines have passenger manifests. Workers at the trade center began with only an uncertain list of thousands of missing people, including residents of 60 nations, that fluctuates faster than they can recover remains.

Of the 276 confirmed dead so far, 206 had been identified.

Identifying the rest “is an enormous task,” said forensic anthropologist Clyde Snow, who pioneered many of the identification techniques now being put to the task.

“The challenges to the recovery people and the forensic scientists are going to be immeasurably greater than we have ever faced before in any disasters in this country,” Snow said.

No one knows how long it will take, how much it will cost, or the emotional toll it will exact from the forensic experts now working in three shifts, 24 hours a day, seven days a week.

As best they can, morgue teams inventory the remains. They note any identifying detail that friends and families of the missing can provide: a spider-web tattoo on a woman from the 100th floor; a red medical alert bracelet worn by a 6-year-old boy visiting his mother on the 107th; a woman’s name tattooed on the arm of a man from the 93rd floor; the half-circle of freckles on the broad shoulder of a broker last seen on the 89th floor.

A Lot of Progress Since First Use of Fingerprints

Forensic specialists have a remarkable array of tools to match fragmentary remains with a name. Since fingerprints were first introduced as evidence of identity in a 1911 burglary trial, analysts have bolstered their diagnostic skills with techniques for facial reconstruction, chemical tests, computerized dental comparisons, X-ray dispersion and DNA analysis.

They can peel fingerprints from charred hands and rebuild burned faces.

They can analyze as many as 70 enzymes in blood, bone marrow and body fluids to put together a distinctive biochemical profile.

From the long bones of arms and legs, scientists can gauge someone’s age, weight, sex, race and muscularity. With enough material, they can even tell if a person was right- or left-handed.

From a single strand of hair, some forensic experts can glean estimates of race, sex and other characteristics. Researchers at the National Institute of Standards and Technology are testing a way to use sophisticated techniques for chemical analysis known as gas chromatography and mass spectrometry to develop a chemical profile from hair samples that can be used like a fingerprint.

But for thousands of the missing, whose photographs are taped to Manhattan’s walls and street poles, smiles may be all that survive.

Teeth could endure in the hellish heat that melted the World Trade Center’s steel beams even when all other human remains were consumed. Dental enamel can withstand temperatures as high as 1,800 degrees Fahrenheit, forensic odontologists said.

As an almost indestructible marker of identity, teeth long have been a mainstay for forensic pathologists.

At the New York City Medical Examiner’s office, 100 dentists have been working in shifts around the clock to assemble the needed X-rays and patient notes to match against teeth recovered from the rubble. They scrutinize each tooth with the intensity of a diamond cutter.

“For us, a tooth stands out like a beacon,” said Jeffrey Burkes, the city’s chief forensic odontologist. He would not discuss the specifics of any case but said the numbers of dead and missing are overwhelming.

“It is a staggering task. Without computers we would be lost.”

When medical files are handed over by relatives, the identifying dental details are entered into a rapidly growing database of the dead. Teeth recovered from the ruins then can be matched quickly against the computerized files.

A single tooth can be enough to restore a name to one of the dead, said forensic expert Tom Glass, who supervised the dental identification of the 168 people killed in the 1995 Oklahoma City bombing.

“You need the right tooth or the right part of the tooth,” Glass said. “Having a piece of the root may be enough, if it has enough unique characteristics.”

Even the fillings in teeth can be revealing. An international team of forensic experts in 1985 identified the remains of fugitive Nazi war criminal Dr. Josef Mengele in part by analyzing the distinctive alloys from dental fillings in six teeth exhumed from a grave.

For many of the missing, however, only DNA--the molecule that binds all people into one human family and yet singles out each person with a unique chemical code--holds the key to identity.

Any tissue that survived the heat and blast should harbor viable DNA.

Under the most extreme conditions, DNA can survive intact inside teeth, protected from heat, moisture and corrosion by the tough enamel, Glass said.

“All you need is a few cells with intact DNA.”

Laboratory technicians can take even minute DNA traces and reproduce enough to create a sample that can be analyzed. They use an automated technique called a polymerase chain reaction, or PCR, that mimics nature’s way of replicating DNA.

“Since we have this DNA technology, I am reasonably assured that everybody [whose remains can be found] will be identified,” said Dr. Donald T. Reay, head of the forensic autopsy committee of the American College of Pathologists. “It is the pure volume that will be overwhelming. I shudder to think how you will do it.”

A Huge Lab, but More Help Needed

Within hours of the disaster, the New York City medical examiner’s office began collecting DNA samples from tissue discovered in the wreckage.

The city has perhaps the largest police DNA lab in the country. Even so, the scale of the required genetic testing is so big that New York officials looked for help. They reached out to 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 Inc. in Rockville, Md. A third company, Applied Biosystems Inc. in the San Francisco Bay Area is providing equipment and other support to the identification effort.

Spread across four laboratories, the testing process is delicate, easily compromised and must adhere to standards of evidence that can hold up in federal court, should any of the results be challenged or become part of a criminal proceeding.

Each DNA sample will take about 10 hours to extract, isolate, amplify and analyze.

So far, officials have collected 6,063 DNA samples that might help identify about 2,100 victims, New York City Police Commissioner Bernard B. Kerik said Monday. Dr. Robert S. Shaler, director of forensic biology for the medical examiner’s office, is preparing to perform DNA testing on as many as 20,000 tissue samples at his laboratories. Forensic experts say that may only be the beginning.

“There are going to be a lot of unassigned parts,” said Murray Marks, a forensic anthropologist at the University of Tennessee at Knoxville. “That will take a lot of DNA work; months and months of work. It’s a huge effort.”

Results from the four laboratories will be cross-checked continually to avoid any wrong identifications.

“There will always be a double-check,” said Ellen Borokove, a medical examiner’s office spokeswoman. “If we don’t have the same answers, we will have to go back and find out why.”

Hoping to Process 30,000 Samples a Month

Lab technicians at Myriad Genetics already have started analyzing DNA samples. Company officials estimate they could process 30,000 samples a month, if necessary. It is the pace of the recovery effort that will dictate the speed of the DNA testing, company President Dr. Gregory Critchfield said.

Myriad’s automated genetic testing lines will search each sample for 13 distinctive stretches of DNA called short tandem repeats. These markers--called STRs--arrayed along specific chromosomes, can be used as a characteristic profile that can “uniquely identify a person,” said Brian Ward, Myriad’s vice president of operations.

“The chance that we would duplicate all 13 [in two people] is less than 1 in 250 trillion.”

Once analyzed, a victim’s DNA will be compared to hair and cell samples obtained from toothbrushes, clothing or hairbrushes the victim may have used.

If those are not available, it is still possible to identify people using DNA taken from blood samples of relatives, but this process is not as definitive. “They can extrapolate from that,” said Norah Rudin, a private forensic DNA consultant based in Berkeley.

Since the attacks, 500 families outside the New York area have come forward to offer DNA samples to identify missing relatives, said Dr. Marcia Eisenberg, senior director for forensic DNA testing at the Laboratory Corp. of America. The company, which has 900 DNA centers around the country, is coordinating genetic collections for the New York medical examiners.

Company officials have fielded calls from as far away as China and Australia.

Even as relatives of the missing pin their hopes on heredity, forensic experts are worried that conditions in the rubble may be so acidic and wet that after several months, some of the DNA may disintegrate before recovery workers can finish clearing all the debris.

“We are concerned about degradation of DNA over time,” Ward said. So far, tissues are being recovered quickly enough that “we are fairly confident we can get DNA out of those samples.”

The most severely damaged DNA samples may end up at Celera, a leading corporate research center that completed the first sequence of the entire human genome earlier this year.

Celera’s scientists are expected to analyze tissue in which the DNA from the nucleus, usually used for analysis, has broken down. Instead of analyzing DNA from the nucleus, which lies at the center of the cell, they will seek genetic material contained in about 10,000 tiny cell structures called mitochondria. The mitochondria contain DNA sequences that are less definitive for identification but more plentiful, smaller and perhaps more robust.

For many families, hope rests on a cell sample swabbed from a relative’s cheek on a cotton-tipped stick, tucked in a plain white envelope and turned over to a lab technician. Extracted from those cells, droplets of DNA are purified and poured into the tiny wells of a laboratory to be tested for a match.

Each well brims with expectation and fear.

New York City officials say they will conduct genetic tests on every piece of tissue recovered from the World Trade Center.

“We’re talking thousands of samples,” Rudin said. “It could take all year.”

However long it takes, the effort is worthwhile, said Harrell Gill-King, a noted forensic anthropologist who runs the laboratory for human identification at the University of North Texas.

“We don’t do forensic science for the dead,” Gill-King said. “We do it for the living.”

*

Times science writer Usha McFarling in Los Angeles contributed to this report.