According to sources speaking to The Post on Friday, the alleged serial killer was identified as a person of interest more than a year ago following a DNA match in connection with the infamous Gilgo Beach murders on Long Island.

Rex Heuermann, 59, was detained in connection with the deaths of four women who were discovered dead, wrapped in hessian, just days apart in late 2010.

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He was finally taken into custody at his office in New York City on Thursday evening, the police said. His arrest is the conclusion of what seems to have been a slow and systematic investigation by the authorities.

Heuermann was apprehended at the Midtown headquarters of his business, RH Architecture.

The building was still swarmed with police Friday, including a New York State Police box truck, two Suffolk Police Highway Patrol cars, a New York State trooper car and a Suffolk County government van.

Sources at the scene told The Post Suffolk County crime labs had been inside the office building, searching them.

State and Suffolk County police have also been at Heuermann’s home since the early hours. A cooler was seized from Heuermann’s run-down home by authorities in the wake of his arrest, according to one source, though it wasn’t immediately clear how it was linked to the investigation.

Heuermann’s arrest is believed to only be tied to the so-called “Gilgo Four” women — and not the other six bodies that were found nearby and eyed as possibly being connected, sources said.

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Fears of a serial killer first emerged when the body of 24-year-old Melissa Barthelemy was discovered along Ocean Parkway on Dec. 11, 2010.

When the body of 24-year-old Melissa Barthelemy was found on December 11, 2010, along Ocean Parkway, suspicions of a serial killer first surfaced.

In the days that followed, the remains of three further women, Megan Waterman, 22, Amber Lynn Costello, 27, and Maureen Brainard-Barnes, 25, were discovered.

The arrest follows the establishment of a specialised Gilgo Beach Homicide Investigation Task Force in February of last year by Suffolk County’s new police commissioner to look into the 10-year-old case.

The Suffolk County District Attorney’s Office, local sheriffs, state police, and the FBI all provided assistance.