9/11 victim identified using first-of-its-kind genetic genealogy technique

Twenty-five years after the September 11, 2001 attacks, New York City is still working to formally identify all of the nearly 3,000 people killed at the World Trade Center.

Now, for the first time, the city's Office of the Chief Medical Examiner and the NYPD Detective Bureau have identified a 9/11 victim using genetic genealogy, which combines DNA testing with family tree research, ABC News has learned.

The family of the newly identified victim, who was an adult female, declined to publicly come forward. She is the 1,651st to be formally identified.

“It's a breakthrough,” Dr. Jason Graham, New York City's chief medical examiner, told ABC News. “I'm delighted to be able to say that we've now applied new methods to the World Trade Center identification efforts, and we have a new identification for the first time in 25 years using new methods, forensic investigative genetic genealogy.”

Such a breakthrough was unimaginable 25 years ago because the methodology did not exist.

“The technology really wasn’t there,” said NYPD Det. Gregory Paduano. “There's a lot of good future with genealogy.”

Forensic investigative genetic genealogy has helped police solve long-term unidentified cold cases. More recently, the medical examiner’s office and the police department have applied it to World Trade Center victim identification efforts.

“We already can see that it's promising,” said Dr. Jennifer Odien, a forensic anthropologist in the New York medical examiner’s office. “Not every case is going to be able to go through genetic genealogy, but we do have DNA profiles that are not matching to our reference samples, so that's the group right now that we're focusing on and that hopefully is going to yield more positive results.”

There are 47 profiles that may be ripe for identification using genetic genealogy, Odien told ABC News.

That represents a small fraction of the nearly 1,100 World Trade Center victims, about 40% of the total, that remain unidentified a quarter-century after the attacks. The Office of the Chief Medical Examiner made a solemn pledge to never stop trying.

“The World Trade Center was the largest mass murder in the history of the United States, and it represents also the most complex forensic identification effort in our history,” Graham said. "And being able to apply new innovations to that identification work is a remarkable way that we can keep our commitment to the families.”