Gilgo Beach suspect Rex Heuermann’s ‘disturbing’ behavior before arrest – and why cops can’t rule out another killer

Suspected Gilgo Beach murderer Rex Heuermann was still engaged in “disturbing” behavior while being tailed right up until his arrest, the top cop in the case revealed — while refusing to rule out the possibility that another Long Island serial killer could still be on the loose.

“I can’t talk about if he was preparing to kill again,” Suffolk County Police Commissioner Rodney Harrison told Newsday Wednesday of married father of two Heuermann.

But “he’s somebody that was still engaging in activity that was disturbing, be it his internet searches, be it engaging in other activities that he shouldn’t be engaging in.

“That’s something I was very, very passionate about, regarding ‘we need to see what his lifestyle is,’” he said of the intense surveillance leading up to his arrest.

Harrison defended calling 59-year-old architect Heuermann “a demon that walks among us” and a “predator” at a press conference the day after the bombshell arrest.

“I’m very confident that Mr. Heuermann’s our subject,” he told the outlet in a video interview.

“Because of my confidence, I’m gonna call him what I wanna call him — somebody that ruined families, somebody who’s a predator, somebody who shattered lives.

“And not just one, several, and there may be more. I didn’t say that there is, but there may be more. If the family members have a problem with me calling him a demon, then I’ll apologize.”

Heuermann pleaded not guilty last month to multiple first- and second-degree murder charges related to the decade-old strangulation deaths of Melissa Barthelemy, 24, Amber Lynn Costello, 22, and Megan Waterman, 27. He is also the prime suspect in the killing of Maureen Brainard-Barnes, 25.

The remains of all four women were found off Ocean Parkway near Gilgo Beach in December 2010.

As for the additional bodies discovered in and around the coastal Long Island enclave – including that of Karen Vergata, whose identity was announced last week – Harrison said police cannot rule out the potential for another serial predator.

“We were able to bring comfort to three families, we’re very close to a fourth one, but we still have more work to do to identify the subject or subjects that were involved with the other bodies that were discovered,” he told Newsday.

When pressed on whether Long Island residents should be worried about another possible killer in their midst, Harrison said he wishes he “could give … an answer.”

“I can’t tell you at this time,” he said.

“Is Rex Heuermann going to be held accountable for the other bodies on Ocean Parkway? Time will tell.”

Harrison maintained that the death of Shanann Gilbert, the Jersey City woman whose May 2010 disappearance sparked the search that led to the discovery of the Gilgo bodies, was “a horrible accident.”

“Myself and the investigators assigned to the homicide squad still believe it was just an incident where she ran into the marsh and unfortunately drowned on that horrible day,” he told Newsday,

Though Gilbert’s autopsy ruled her cause of death undetermined, the lawyer representing her estate maintains that a second examination conducted at the family’s request revealed she died from strangulation.

Harrison, a 30-year NYPD veteran, said he formed the Gilgo Beach task force shortly after he became commissioner in December 2021 – eleven years after the so-called “Gilgo Four” were found.

“When I found out [from homicide chief Det. Lt. Kevin Beyrer] that there was one investigator assigned to this case, I was like, ‘this case is never gonna be solved like that, especially if this person, this detective, is also catching other cases,’” he explained.

Harrison initially increased the number of full-time investigators to four.

A few months later, on March 14, 2022, Heuermann was identified as a suspect after a state police officer found his Chevrolet Avalanche on a database that Suffolk County authorities did not have access to.

The vehicle, which was later seized in South Carolina, matched the description of the car last seen at Costello’s home before she vanished, prosecutors have said.

From March 2022 through his arrest last month, Heuermann was surveilled in a “host of different ways,” Harrison told the outlet.

FBI Special Agency Craig Matteo eventually swiped the pizza crust and napkin that linked Heuermann’s DNA to the burlap with Waterman’s body – though Harrison noted that the FBI almost did not join the task force.

“They were reluctant at first. They were concerned about, I guess, some past relationships where they weren’t necessarily part of being inside the loop of the case.

“So I reassured them, ‘that’s not something you have to worry about any further. I need you, I need your expertise,’” Harrison said, tacitly referring to the many controversies under disgraced ex-police chief James Burke.

The DNA evidence, Harrison continued, was “instrumental” in making the arrest.

“Once we got Rex in our sights, we had to figure out how to collect his DNA. That was something that [the FBI] really had a major role in, gave us some guidance in sending us to the right labs,” he said.

“Once we got those matches, I don’t think I need to tell you anything else, that was really a place where we went from reasonable suspicion to probable cause.”

Now that Heuermann is in custody, Harrison added, the task force still meets daily at the Suffolk County Police Academy in Brentwood.

The group currently includes a sergeant and three detectives who work on the case full-time, in addition to FBI, state police, the sheriff’s office, and investigators and prosecutors from “our pit bull of a district attorney Ray Tierney.”

Police investigators spent over a week combing through the Massapequa Park home Heuermann shared with his wife, Asa Ellerup, and two adult children.

Aside from the 279 firearms taken from a vault inside the South Shore native’s home, police have declined to detail any additional evidence that was found on the property.

At the time of his arrest, a court document stated that Heuermann continued to proposition sex workers and viewed child pornography in the years after he allegedly killed the Gilgo Four.

Phone records also linked him to the burner cells used to contact the victims and even taunt their families.

Also on Wednesday, a judge ordered Heuermann to submit a cheek swab DNA sample for additional testing in the investigation.

His legal team had argued that the prosecution did not have “probable cause” to demand the material.