The arduous task of identifying the victims of the World Trade Center terrorist attacks is still years from completion. Investigators have identified 1465 people from remains recovered from Ground Zero, just over half of those presumed killed.
Knowing for certain that a loved one has been killed is a vital part of coming to terms with the loss. In an effort to help relatives understand why the investigation is taking so long, the forensic team is allowing the families of victims to visit their labs every other week. “That’s something we don’t normally do,” Lydia de Castro at the Office of the Chief Medical Examiner (OCME) of New York, told New Scientist.
As well as the emotional limbo, there are practical issues at stake. For instance, the investigators have already carried out paternity analyses on DNA profiles from 10 to 20 of the victims to establish whether a victim’s estate is liable for the maintenance of children they are presumed to have fathered. Other relatives need confirmation to activate wills and finalise life insurance claims.
“No one knows how long the identification process will take,” says Zoran Budimlija, a forensic scientist at the OCME. Money has been set aside to fund the search until 2005, but it seems unlikely that work will be completed by then.
The scale of the forensic investigation into the 11 September attacks is huge. Over 20,000 pieces of tissue, tooth or bone were recovered from the 1.7 million tonnes of debris transported to Staten Island, Amy Mundorff of the OCME told the American Academy of Forensic Sciences conference in Chicago.
Most fragments are so tiny that traditional techniques for guiding identification, such as working out the age, sex and height of a body, have been largely set aside. Instead, investigators are trying to match DNA profiles from the remains to DNA from personal items belonging to the missing.
If there is an upside at all, it is that forensic scientists have learned a lot from the grim and tortuous process that will make it easier to identify victims in a future mass disaster.
Researchers have worked on two techniques in particular – DNA IQ extraction, a way of extracting genetic material from solid objects such as bone, and analysing single nucleotide polymorphisms, variations in individual base pairs on the genome that can be extracted from tiny amounts of DNA.
“If you don’t learn from what you have, you lose sight of why you’re there,” says forensic scientist Steve Symer at the University of Tennessee in Memphis.