LI cops scour woods for clues in decades-old serial killer case – not tied to Gilgo slayings

The extensive police search of a remote area on Long Island is not tied to suspected Gilgo Beach killer Rex Heuermann — but to another possible serial killer, police sources told The Post.

Cops are looking for new evidence related to the 1993 murder of Sandra Costilla — and they are hoping to finally tie the case to convicted killer John Bittrolff, according to sources with knowledge of the Suffolk County case.

Cops have also shifted their focus from the woods in Manorville to North Sea, a hamlet located within Southampton Town.

That’s where Costilla, 28, of Queens, was found savagely beaten and strangled by hunters on Nov. 20, 1993.

Bittrolff, who is in prison after being convicted of killing two other women on Long Island, was previously named as a suspect in Costilla’s murder, but has never been charged.

Authorities on Saturday continued combing through the dense North Sea woods, including with cadever-sniffing dogs.

It was unclear what new information led detectives back to both locations — or if they have found anything pertinent during the searches, the sources said.

Bittrolff, a 57-year-old former carpenter, lived in Manorville, not far from where cops were conducting their search this past week.

He was arrested in 2014 for the murders of two women: Rita Tangredi, 31, a known sex worker found dead November 2, 1993, in East Patchogue, and Colleen McNamee, 20, who was found killed on January 30, 1994, in a wooded area along William Floyd Parkway in Shirley.

In 2017, jurors found Bittrolff guilty of second-degree murder in both cases. He is now serving 50 years to life.

Investigators have never been able to pin Costilla’s unsolved murder on Bittrolff.

Multiple police sources confirm Bittrolff was, for years after his arrest, the lead suspect in the Gilgo Beach murders investigation.

After his sentencing, Suffolk County prosecutors revealed Bittrolff was also suspected in at least one of the 10 murders attributed to the Gilgo Beach killer.

The torsos of two of the Long Island Serial Killer’s victims, Jessica Taylor and Valerie Mack, were found in Manorville — three miles from Bittrolff’s residence.

Police have noted Tangredi’s adult daughter said she was best friends with Melissa Barthelemy, one of the first victims discovered at Gilgo Beach.

Prior to disappearing, police said Barthelemy made several calls to a Manorville number. Police have never said who the number was registered to.

Sources confirmed police ended up dismissing Bittrolff as a Gilgo Beach suspect months before arresting Heuermann for four of the grisly murders, including Barthelemy’s.

Suffolk District Attorney Ray Tierney later publicly said Bittrolff was not involved in the Gilgo Beach serial murders.

Heuermann has pleaded not guilty to the four charges of murder he faces.