Long Island investigators identified the remains of six cold case victims dating back 50 years — including one possibly murdered by the infamous Jersey Shore “Thrill Killer.”

The same cutting edge DNA testing that helped nab notorious Gilgo Beach killer Rex Heuermann in 2023 was used to identify the John and Jane Does, three of whom are believed to be murder victims.

“We’ve given back their names,” Suffolk District Attorney Ray Tierney told reporters Thursday. “We have made full progress in restoring the identities of these individuals, providing answers to their loved ones and advancing the pursuit of justice on their behalf.”

Among them was a victim long-known as “Montauk Mary” — an elderly woman discovered with four gunshots to the chest in the coastal town in 1978 — who was identified as 73-year-old Sofia Margherita Marrone and is believed to have been murdered by serial killer Richard Biegenwald.

Marrone’s body was far from her New Jersey home — she was last seen alive leaving the Garden State’s Shore Memorial Hospital down the road from her Pleasantville residence days earlier.

Exactly how Marrone ended up hours away in Montauk remains unclear but investigators suspect she may have fallen victim to Biegenwald, who was known as the “Thrill Killer” and murdered at least six victims across the Jersey Shore before his 1983 arrest.

Biegenwald is suspected in Marrone’s murder because she was riddled with the exact same bullets he used in his killings — .22-caliber short rounds — though police clarified it couldn’t be said for certain yet whether he was the gunman. Biegenwald died behind bars in 2008.

The other victims included 41-year-old Ramon Perez Y Rivera — long known as Raymond Doe for a tattoo on his body — who was found in 1976 by hunters in Deer Park with a gunshot wound to the abdomen. The Puerto Rico native was living in Brooklyn when he died.

Antionette Rugg, 27, was also identified. She was found in Islip in 1978 after a dog began scratching at the ground and dug up a human skull, while a belt was also found tightly cinched around her neck.

The other victims were identified as 32-year-old South Korean Kyong-Ok Kim — found in Riverhead Town in 1990 and whose cause of death remains under investigation — and 27-year-old Omelios Steward and 27-year-old German Andreas Kupke, who were found in 1990 and 1999. Steward was believed to have drowned while Kupke’s cause of death remains unclear.

“We have made full progress in restoring the identities of these individuals, providing answers to their loved ones and advancing the pursuit of justice on their behalf,” Tierney said.

Suffolk County still has some 244 unsolved death cases spanning from 1970 to 2025.

And there are about 210 victims in those cases still unidentified, with Tierney explaining his office was still working to identify them and would use the same DNA tech to investigate if they could.