Time has not been a friend of the forensic teams. Victim No. 1,641 — a man who, at his family’s request, has not been publicly named — became known to them a month ago. This was nearly two and a half years after No. 1,640 was identified: Matthew David Yarnell, a 26-year-old technology specialist who worked on the 97th floor of the south tower. Before that, six months had gone by since No. 1,639: Patrice Braut, 31, the lone Belgian citizen among the victims. He worked on the 97th floor of the north tower.
“It’s a slow go,” Dr. Sampson said. “We’re now down to the ones that are very difficult to get useful DNA.”
The genetic material that’s available is sometimes no more than the tiniest patch of flesh. Some remains lay in the wreckage for weeks, months, even years — degraded by water, burning jet fuel and all manner of debris from the downed buildings. In addition, bacterial DNA intermingled with human matter. “It was the worst combination of events you could have for a DNA specimen,” said Dr. Sampson, who has been the city’s chief medical examiner since December 2014.
Recent scientific advances, including what she described as a bone-extraction technique, made it possible to identify the 1,641st victim. That gives her hope that the process is not stuck. “I am optimistic we will identify more people,” she said. “But do I think we will be able to identify every single person? Probably not.”
Apparently, relatives of the victims have not given up. None of them have told the medical examiner’s office that, after the passage of so much time, they no longer care about matching slivers of remains to their loved ones. “We work very closely with the families,” Dr. Sampson said. “We know every family’s wishes as for what they want us to do.”
Since 2014, unclaimed remains have rested 70 feet underground in a repository at the National September 11 Memorial & Museum in Lower Manhattan. Only members of the medical examiner’s office may enter the area (though no laboratory work is done there). Next to the repository is a quiet space known as the reflection room, reserved for Sept. 11 families and their guests. Not surprisingly, the anniversary is a time of pilgrimage there. In a typical month, 20 or so people go to the room. On Sept. 11 alone last year, 65 visited.
Just about every week, a few families will call the medical examiner’s office with questions, mostly of a technical or administrative nature. Still,…