The Suffolk County Police Department has identified a former Jane Doe, believed to be a victim of the so-called Long Island Serial Killer, as Valerie Mack.

In a Facebook post Thursday, the SCPD said Mack also went by the name Melissa Taylor, and she disappeared in the spring or summer of 2000 at the age of 24. At the time, she was working as an escort in Philadelphia and she was last seen in the area of Port Republic, New Jersey.

Per Gilgo News, a website created by the SCPD to track updates in the case, Mack’s partial remains were found in November 2000 in a wooded area in Manorville, New York (it’s believed her remains had been dumped there a few months prior in September). Eleven years later, in April 2011, additional remains belonging to Mack were found much further away on Ocean Parkway, near Oak Beach. That location, however, is not far from Gilgo Beach, where the remains of several other victims had been found.

Mack was identified using genetic genealogy, reportedly a first of its kind for a police investigation in New York State. SCPD Commissioner Geraldine Hart said in a video statement that the process allowed investigators to establish a genealogy profile of the victim, which provided new leads to pursue. Hart said investigators followed the trail to New Jersey, where they spoke with potential relatives who provided additional DNA samples, which were then used to narrow down and confirm Mack’s identity.

“It is our hope that our efforts bring some sense of closure and peace to Valerie’s family,” Hart said. She added: “Valerie Mack’s identification represents progress in this investigation but there is much work left to do. As detectives continue to relentlessly pursue leads related to her murder, we ask members of the public, friends, family and associates of Valerie Mack to provide whatever information they have about her and the circumstances which may have led to her death.”

The Long Island serial killer case is one of the most notorious unsolved mysteries. The killer targeted mostly sex workers and is believed to have killed upwards of 20 people.