Gilgo Beach murders: Suffolk County DA details Rex Heuermann’s arrest

‘Avalanche’ of evidence

Prosecutors said they have an "avalanche" of evidence against Rex Heuermann, the man suspected of the Gilgo Beach murders. 

Heuermann, a Long Island architect, has been charged with murder in the deaths of three of the 11 victims and a long-unsolved string of killings. 

Prosecutors say Heuermann had a burner phone and had burner phones and a long Internet history containing at least 200 searches about the investigation into the Gilgo murders.

Suffolk County District Attorney Raymond Tierney joined Good Day New York with details about the special task force and investigation that led to the arrest of Heuermann.

Tierney first got into office in January 2022 and that was when he formed the task force.

"After reviewing all the evidence in the case, we had sort of honed in on this," Tierney said.

Detailing Huermann's arrest:

There is potentially a fourth person Heurmann has been linked to.

"Towards last Thursday, we had given the potential danger and also potential disclosure of our investigation," Tierney said.

Tierney says the defendant lived a very atypical, bifurcated life. Heurmann was still continuing to use burner phones and communicating with sex workers. 

"Obviously, we had him under surveillance, but still. So, you know, early evening, Thursday, you know, the decision was made. You know, we need to we need to to to put him in custody," Tierney said.

"The smoking gun was, first of all, forming the task force and bringing in really great analysts and investigators from a number of agencies and putting them directly in contact with our prosecutors," Tierney said.

Tierney said March 14 was when they first heard the name Rex Heurmann come up as a suspect. Officials realized he owned a Chevy Avalanche, which was the car driven by the man that saw the last victim, Amber Lynn Costello who is alive.

Officials described the suspect as:

• Very distinctly large man
• Heavily built
• Glasses
• Dark thick hair

"When we saw that Heurmann matched that description, but not only that, earlier in the investigation in 2012, the FBI had established these areas of interest in Massapequa Park, as well as Midtown Manhattan. As far as phone cell phone usage in areas where these cell phones were being used. And Heurmann, he lived in Massapequa Park, and he worked in Midtown Manhattan and that within that same area," Tierney said.

Tierney told FOX 5 NY that those were very compelling factors.

"And then, of course, then now you go back to the crime scene, and you've got these five question hairs which were answered well for regular DNA, but we did mitochondrial," Tierney said.

Tierney added that there wasn't much evidence except for the hairs that were originally not suitable for nuclear DNA testing. 

He said they were able to do mitochondrial DNA and DNA profiles. 

"We got in a sample from the defendant and some of his family members. And the profile from those samples matched some of the hairs found on the bodies, specifically hairs from a human and two hairs from his wife," Tierney said.

Tierney got the chance to meet some of the victims' families and said it was a "powerful thing."

"That's a moment I don't think, you know, any of us will ever forget, because they had waited for so long. And, you know, periodically you do meet up with them. And of course, we didn't tell them why we were coming to see them. And so when we saw them, and they knew," Tierney said.

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Tierney said he is charged with first- and second-degree murder in connection with the deaths of three victims – Melissa Barthelemy, Megan Waterman and Amber Costello. 

"We have these four cases in our sights. We're going to complete that, and then we're going to keep on going. And it doesn't matter what I think, it matters what I can prove. And we're going to continue to work through this case. And, you know, we have a great team, and we feel good about things," Tierney said. 

Tierney asks if anyone has any information to reach out to hotlines or the DA's office. 

The Associated Press contributed to this report.