Long Island prosecutors have the green light to use crucial DNA evidence in their case against accused Gilgo Beach serial killer Rex Heuermann, a judge ruled Wednesday.

The bombshell ruling by Judge Tim Mazzei marks a massive victory for Suffolk County District Attorney Ray Tierney, whose case against the hulking architect hinged almost entirely on DNA matches linking Heuermann to seven sex workers he is charged with killing between 1993 and 2010.

“The science was on our side and that’s why we won,” Tierney told reporters Wednesday.

The accused killer’s wife, Asa Ellerup, was in court but did not comment after the ruling.

Heuermann was arrested outside his Manhattan office in July 2023 and charged with the murders of three sex workers whose bodies were dumped along desolate stretches of Long Island.

He was later charged with four more deaths, and is now accused of killing Valerie Mack, 24; Melissa Taylor, 20; Megan Waterman, 22; Melissa Barthelemy, 24; Maureen Brainard-Barnes, 25; Sandra Costilla, 28, and Amber Lynn Costello, 27.

Their deaths remained unsolved until Suffolk County police reopened the case at Tierney’s urging.

Investigators were aided by new technology that allowed “degraded” DNA samples, such as the hairs found on the victims, to be tested and linked to the crimes.

Heuermann’s attorney, Michael Brown, has been critical of the evidence, calling it “magic.”

In court Wednesday, Brown argued that Astrea Labs, the company that did the DNA testing, is not licensed in the Empire State and therefore using the results violates health laws.

But Mazzei nonetheless ruled that prosecutors may use the evidence at the upcoming trial.