Suffolk County District Attorney Ray Tierney refuted several of the objections made by the first witness called by the defense of alleged Gilgo Beach killer Rex Heuermann over two long days of cross-examination at Suffolk County Court in Riverhead between June 17 and 18.
The Suffolk County district attorney focused on Nathaniel Adams background, speaking engagements, and work. He argued that the 38-year-old systems engineer has a pattern of repudiating not only newer DNA testing methods but also those that courts and the scientific community have widely accepted. Tierney said that Adams rejects "almost every modality of DNA testing, including those deemed widely admissible by the courts in this country."
Tierney analyzed how Adams reviewed the California-based lab's procedures and then flipped the script on him—comparing the "several pages of notes" that Adams provided to the court on June 18 to the 28 terabytes of data that he claimed Astrea labs had provided to the district attorney's office.
"Your review of terabytes of data only generates seven pages of notes," Tierney said. He also compared the work Adams did on Astrea to a software development chart that he included in his 57-slide PowerPoint presentation he showed during his testimony, saying that "if we evaluated you in adherence to the formal process, you would be in the zone of chaos."
Adams, who works at Forensic Bioinformatic Services in Fairborn, Ohio, stated that Astrea Labs failed to adhere to 21 nationally accepted verification and validation standards, which were necessary to ensure the software performed accurately.
"It's unreliable," he said to Heuermann's defense attorney Danielle Coysh in front of state Supreme Court Justice Timothy Mazzei in Suffolk County Court on June 17.
He was the fourth witness called in the case's
Frye hearing. The legal proceeding, also known as a general acceptance hearing, is used to determine that scientific evidence presented in court is widely accepted and considered valid within the relevant scientific community.
Astreas' methods were not consistent with the standards of the Institute of Electrical and Electronic Engineers, according to Adams. The institute represents around 150,000 engineers, scientists, and allied professionals in the United States.
The specific standard that Adams was referring to pertains to the verification and validation processes used to determine whether a product meets the requirements of its development and that it fulfills its intended purpose and user needs.
Adams argued that "at a variety of phases," Astrea was "missing important verification steps."
Tierney pushed back on the claim during his cross-examination, pointing out that the institute concedes that the standards are not binding.
"Use of an IEEE standard is wholly voluntary," Tierney read from a disclaimer written by the IEEE. "The existence of an IEEE standard does not imply that there are no other ways to produce, test, measure, purchase, market, or provide other goods and services related to the scope of the IEEE standard."
Adams' educational background was a subject during both days of the testimony. The prosecution argued that he lacked the expertise needed to critique Astrea's methods, comparing his bachelor's degrees to those of the
three witnesses they called, who all possessed doctorate degrees in scientific fields.
Coysh pushed back on those claims during her redirect examination, pointing out that it is typical for software engineers only to have a bachelor's degree.
She also asked Adams if his possession of a doctorate would change his opinions on Astrea's validity. Tierney objected to this question, and Mazzei upheld it. Coysh followed up by asking Adams if having a doctorate would change any of the evidence in this case, to which Adams responded, "No."
Tierney objected to the question again, but did not get the same result. "I'll allow that," Mazzei said. The next hearing is scheduled for July 17. The prosecution has declined to comment until the hearing concludes.
Outside the courtroom, Heuermann's court-appointed defense attorney, Michael Brown, said that his client was pleased with how Coysh handled the testimony and looks forward to the opportunity for his case to be tried.
"He's very anxious to get to trial, but he's a patient man," Brown said. "He appreciates the fact that we're working for him and making sure we cross our t's and dot our i's before we get to trial. So he's looking forward to his day in court."
Brown also had some positive words for his opponent.
"He (Tierney) did a great job on cross-examination," Brown said. He added that he thought it was great to show the young assistants that "your boss can try a case and try it well."
Heuermann, a 61-year-old who lives in Massapequa Park, is charged with the murders of seven people: Melissa Barthelemy, Maureen Brainard-Barnes, Amber Lynn Costello, Megan Waterman, Jessica Taylor, Sandra Costilla, and Valerie Mack. He has pleaded not guilty to all charges and has maintained his innocence since his arrest.
No trial date has been set for the case, although Brown said that the earliest a trial date could be was early 2026, but added that "there are still lots of things we need to do."
