Gilgo Beach killings: Judge to rule on hair DNA admissibility Sept. 3

The Suffolk judge presiding over the Gilgo Beach serial killings case will issue a decision on the admissibility of nuclear DNA evidence in the case Sept. 3, he announced following a brief conference with attorneys Tuesday.

State Supreme Court Justice Timothy Mazzei set an Aug. 15 deadline for the attorneys representing accused killer Rex A. Heuermann to file closing briefs on the DNA issue and for prosecutors to file their brief by Aug. 22.

Heuermann, charged in the killings of seven women between 1993 and 2010, will next appear in court when the monthslong hearing draws to a close Sept. 3. He has pleaded not guilty to multiple first- and second-degree murder charges.

"We'll have a decision on [Sept. 3] and that decision is going to dictate whether or not the court believes that it's generally accepted within the relevant scientific community or not," Heuermann defense attorney Michael J. Brown said outside court Tuesday. "If he decides it is and this evidence comes in at trial, we still have the opportunity to cross-examine these witnesses and attack all the same issues [at trial]."

Brown said he believes through direct testimony from a pair of defense witnesses, and cross-examination of a group of genealogy experts who testified for the prosecution, that the defense has effectively demonstrated the whole genome sequencing techniques used by an outside lab to link Heuermann to six of the killings does not meet the general acceptance standard used in New York courts.

"It's novel," Brown said of the techniques used by Astrea Forensics. "It has not been used anywhere around the country other than Idaho, which has a much different and lower standard. If the judge permits it in, he permits it in, but hopefully he agrees with our position."

Brown, who appeared in court without his client present Tuesday, said he intends to file additional pretrial motions following the Sept. 3 conference and that he anticipates the case heading to trial regardless of the judge's decision.

Suffolk County District Attorney Ray Tierney, who did not attend Tuesday's conference, has declined to comment on the case while the DNA hearing goes on.

Heuermann, 61, of Massapequa Park, has pleaded not guilty to murder charges in the killings of Melissa Barthelemy, Maureen Brainard-Barnes, Amber Lynn Costello, Sandra Costilla, Valerie Mack, Jessica Taylor and Megan Waterman.

Richard Green, co-founder of Astrea Forensics in Santa Cruz, California, testified during the hearing, which began in March, that whole genome sequencing has become prevalent in criminal cases and his lab’s proprietary technology applying the science has begun to assist law enforcement across the country even if the work hasn’t made its way into many courtrooms. It will soon be the primary method for generating forensic genetic data, Green told the court April 17.

Population geneticist Kelley Harris, also testifying for the prosecution, described Astrea's proprietary software, IBDGem, as an "elegant and powerful" tool and said the likelihood ratios it generates are widely accepted in science.

"It's embarrassing for our criminal justice system that a method like this wasn't the state of the art years ago," Harris, an associate professor of genome sciences at the University of Washington, told Mazzei March 28.

Defense witness Dan Krane, a professor of biological sciences at Wright State University in Ohio and the president and CEO of Forensic Bioinformatic Services, told the judge last week the Astrea analysis is a "paradigm shift" and "radically different" from established methods.

"It is the new kid on the block," Krane said July 18. "We've had one paper that describes what IBDGem does."

Mazzei is also yet to issue a decision on a defense motion to separate the cases. Brown said he expects that decision would come sometime after the Sept. 3 court date.

Heuermann, a Manhattan architectural consultant, has remained incarcerated at the Suffolk County jail in Riverhead since his July 13, 2023, arrest.

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.