Prosecutors are strengthening their DNA evidence against suspected Gilgo Beach killer, Rex Heuermann, who has now been charged with the murder of a fourth victim.

Through a forensic analysis of a hair found on the belt buckle used to restrain victim Maureen Brainard-Barnes’s body, detectives obtained nuclear DNA results that they said are nearly identical to Asa Ellerup, Heuermann’s wife.

Nuclear DNA shows a more complete genetic profile than mitochondrial DNA and eliminates almost all doubt that the DNA could belong to anyone else.

Suffolk County District Attorney Ray Tierney said lab results show DNA recovered from the hair is 7.9 trillion times more likely to be Asa’s DNA than anyone else’s.

“Nuclear DNA existed in the hair since they were first recovered in 2010 and now the science has caught up,” said District Attorney Tierney. “I would say that is a good break for justice, a good break for the investigation. Nuclear DNA is the gold standard.”

For the first time in this case, prosecutors revealed that a hair sample from Heuermann’s daughter, Victoria, was found on Gilgo Beach victim Amber Costello.

In May 2023, undercover agents followed Victoria onto an LIRR train from Penn Station. A clandestine photo revealed in court documents Tuesday shows Victoria was drinking a “Monster Java” energy drink on the train.

Detectives watched her throw it out when she got off at the Massapequa Park station. They took it out of the trash and used it to test for her DNA.

Prosecutors said Heuermann's family was hundreds of miles away during the murders.

“That makes it an even stronger case,” said David Sarni, a retired NYPD detective and adjunct professor at John Jay College of Criminal Justice. “Having family members’—in this case, his wife and daughter's DNA—at the scene or recovered from a murder and they're not there, where else would it have come from?”

According to court documents, travel records, cellphone bills and financial statements show Ellerup and her children were out of state at the time each victim disappeared. Some of these documents were obtained through searches of Heuermann’s storage unit after his bombshell arrest.

“If I live with somebody, their DNA is all over me—their hair, their clothing fibers,” said Michael Alcazar, retired NYPD detective and adjunct professor at John Jay College of Criminal Justice. “In this case, Heuermann brought that DNA potentially, this is what they're trying to prove, to the crime scene and to the victims’ bodies. That's very damning evidence.”

Prosecutors have said Brainard-Barnes’ cellphone was used to check voicemail three days after she disappeared. Cell site data show it happened on July 12, 2007, near the Long Island Expressway in Islandia. According to court documents, cellphone records place Heuermann in the same place around the same time.