Suffolk County cops ignored a key tip in the grisly Gilgo Beach murder case for over a decade — and had a general desciption of the suspect and a make and model of car he drove which they failed to act upon for 13 years.

It was only when a new task force went back over evidence in the case and re-interviewed a pimp that the clues pointed to Rex Heuermann, a 59-year-old architect who is now charged with three counts of murder.

The crucial tip came from the pimp for Amber Lynn Costello, one of three women allegedly killed by Heuermann in 2010.

He was interviewed by cops soon after the murders and identified the killer as a bulky “ogre” who drove a distinctive Chevrolet Avalanche when last seen with the victim.

It was only when ex-NYPD Chief Rodney Harrison took over as Suffolk County police commissioner last year and reopened the case that the dots started to get joined.

Just one month later, in March 2022, a newly formed task force to investigate the murders had Heuermann in their sights.

“This was the first time Rex Heuermann’s name had come up and the first time that he had been identified as a potential suspect,” State Police Major Stephen Udice, commander of Troop L, said at a press briefing Monday.

“At that time, the task force worked as a team to move forward with that information, and the investigation ultimately confirmed that Rex Heuermann was in fact the individual responsible for at minimum the deaths of three women,” Udice told reporters.

Heuerman, a married father of two from Massapequa Park with an office in Midtown Manhattan, also fits the pimp’s “ogre” description — he’s 6-foot-6 and weighs about 270 pounds.

He was arrested last week outside his Fifth Avenue offices and charged with three counts of murder in the deaths of Costello, 27, Melissa Barthelemy, 24, and Megan Waterman, 22.

He’s also the prime suspect in the slaying of another woman, Maureen Brainard-Barnes, 25 — with the victims known collectively as the “Gilgo Four.”

Prosecutors said at Heuermann’s arraignment on Friday he solicited escorts on Craigslist and other sites, occasionally using unregistered ‘burner’ phones, which he later dumped, to make contact with his victims.

Suffolk County District Attorney Ray Tierney said at the arraignment that cops also found “a lot of torture porn” and “depictions or women being abused, raped and even killed” in Heuermann’s posession after his arrest.