Forty percent of the 2,753 people who died at Ground Zero have not been identified, according to the Office of the Chief Medical Examiner.

Last month the lab announced its first identification of previously unknown remains using this breakthrough technique, marking the first success in a year of work.

The method blends traditional DNA testing with genetic genealogy. Police officers from the NYPD build family‑tree searches, while an outside laboratory creates a whole‑genome sequence from the unidentified bone.

If a potential relative appears in the family tree, the medical examiner’s office confirms the link by comparing the new DNA profile with the family’s sample. This two‑step verification reduces false matches.

Mark Desire, assistant director of forensic biology at the New York City Office of the Chief Medical Examiner, said there are 47 sets of remains that have complete DNA profiles but do not match any of the 17,000 reference samples families have already provided.

Each successful match can give a family a name, a story, and a chance to mourn properly, even 25 years after the attacks. The new approach promises to close more of the remaining gaps.