Gilgo Beach killings: Defense says it wants to exclude DNA evidence against suspected serial killer Rex Heuermann at trial

The admissibility of the DNA methods used to charge alleged Gilgo Beach serial killer Rex A. Heuermann in six killings will be the subject of a hearing next spring, as his defense looks to exclude the evidence at trial, attorneys and the judge presiding over the case said Wednesday.

Defense attorney Michael J. Brown, of Central Islip, is alleging the DNA expert prosecutors intend to call to testify will speak to unproven methods of genetic testing that do not meet the Frye Standard, which requires an expert's opinion to be "generally accepted" within their scientific community. The testing, conducted by Astrea Forensics of Scotts Valley, California, used proprietary DNA methods to recover data from degraded hair samples — methods never before presented in a New York court.

"These [DNA] results are not fair," Brown said following Heuermann's appearance before State Supreme Court Justice Timothy Mazzei. "They shouldn't come into evidence because [Astrea] is not accredited [in New York State]; they're not a forensic-accredited crime lab. There's no science behind it, in the sense that it has not been peer reviewed."

Heuermann, 61, of Massapequa Park, has been charged in the killings of six women: Melissa Barthelemy, Megan Waterman, Amber Lynn Costello, Maureen Brainard-Barnes, Jessica Taylor and Sandra Costilla. Degraded hair samples found at the crime scenes were used to connect Heuermann to each of his alleged victims.

But Brown, who called Astrea's work "magic," said the only peer analysis the defense uncovered found the methods used by the lab to be faulty. Officials with Astrea did not immediately respond to a request for comment.

Suffolk County District Attorney Ray Tierney conceded a Frye hearing is necessary because the nuclear DNA methods used by the outside laboratory have not been presented in New York State courts.

"SNP [single nucleotide polymorphism genetic testing] DNA is an issue of first impression for New York State," Tierney said. "So we'll have to go through that ... Frye process."

Mazzei has asked both sides to meet in the coming weeks to reach a consensus on the parameters for the hearing before the judge sets a date. Mazzei said Wednesday he intends to set the hearing date, and possibly a date for trial, at Heuermann's next appearance on Dec. 17.

Under current state Department of Health regulations, private laboratories doing DNA analysis for police and prosecutors needed to be vetted and issued permits by the DOH. Currently, four such labs have been given approval, a state Health Department spokesperson said.

Failure of a private laboratory to get a DOH permit may subject it to civil monetary penalties, the agency said in a statement to Newsday. But it was unclear if any evidence developed by a lab lacking a permit has ever caused a problem in using the evidence in court.

And because the Gilgo Beach task force is working with the FBI, investigators can use the federal agency to access any laboratory without being limited by state rules, officials have said.

Suffolk County Assistant District Attorney Nicholas Santomartino said prosecutors turned over to the defense Wednesday the last of the DNA evidence in the six killings Heuermann has been charged with. Brown assured Mazzei that evidence in the first four charged killings has already been reviewed by a defense expert and that he intends to transfer the newly turned-over evidence, which relates to two alleged victims added to the indictment in June, Costilla and Taylor, within the coming days.

Santomartino said prosecutors have also nearly completed electronic discovery in the case, having now turned over almost all of the evidence found on hundreds of devices seized in search warrants executed at Heuermann's home, office and at storage facilities.

Brown downplayed the significance of that evidence, but said the defense continues to explore filing motions seeking hearings on other issues related to the case, in particular to separate the first four charged killings from the others and also for a possible change of venue.

Both issues relate to concerns over a poisoned jury pool, Brown said.

"It is going to be very important for us to sever the fifth and sixth victims in the indictment from the first four, meaning try those separate and apart," Brown said.

Brown said there is "virtually no evidence" connecting his client to Costilla and Taylor, whose killings date back to 1993 and 2003, respectively.

"With the Gilgo Four, it's our position that the evidence is very weak, but we can deal with that," Brown said. "By putting five and six into the indictment, there's virtually no evidence, and all it does is try to poison the jury about [the Gilgo Four]."

Tierney said investigators continue to look at Heuermann in connection with other killings and would not rule out future indictments before the December conference.

"We speak in indictments and we will charge when we're ready to charge," Tierney said.

Heuermann, a New York City architect, has pleaded not guilty to multiple first-degree and second-degree murder charges in connection with the six killings.

The investigations span 30 years, from the 1993 death of Costilla to Heuermann’s arrest in July 2023. Heuermann, who was first indicted in the killings of Barthelemy, Waterman and Costello, was charged in Brainard-Barnes’ death in January, and with killing Taylor and Costilla in June.

Barthelemy, Waterman, Costello, Brainard-Barnes and Taylor are among 11 sets of human remains found at Gilgo Beach between 2010 and 2011. Additional remains of Taylor were located in Manorville shortly after her disappearance in 2003. Costilla’s body was found in North Sea around the time of her death in November 1993.

Each of the women engaged in sex work, prosecutors have said. They have also alleged Heuermann frequented sex workers and studied research on serial killers to evade law enforcement during the decadeslong investigation.

With Anthony M. DeStefano

By Grant Parpan

grant.parpan@newsday.com@GrantParpan

Grant Parpan covers Suffolk County courts and federal courts for Newsday. A Long Island native, he joined Newsday in 2022.