Suspected Gilgo Beach serial killer Rex Heuermann's cheek swab DNA matches a sample collected from a pizza box in a trash can outside his Manhattan architecture firm, prosecutors revealed in court Wednesday morning. 

"It's consistent with our expectations, so that's good," Suffolk County District Attorney Ray Tierney said after Heuermann's court appearance Wednesday. The DA is also the lead prosecutor on the case.

Heuermann's defense attorneys, Danielle Coysh and Mike Brown, had previously tried to block authorities from taking a cheek swab, arguing that prosecutors had failed to show probable cause. The judge disagreed.

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According to court documents, the FBI observed Heuermann discarding the box outside his Manhattan office before his arrest in July.

With it, lab testing allegedly found DNA matching evidence at the Gilgo Beach crime scene with the body of victim Megan Waterman, 22.

Heuermann has pleaded not guilty to six counts of murder for the deaths of Waterman, Amber Costello, 27, and Melissa Barthelemy, 24.

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Tierney also indicated that Heuermann may soon be charged in the death of a fourth woman, Maureen Brainard-Barnes, 25, whose remains were found near the other three in the brush alongside Ocean Parkway near Gilgo Beach.

Heuermann has previously been identified as the prime suspect in her death.

In addition to the pizza box DNA and a description of the suspect from Costello's former pimp, investigators also used phone records to zero in on Heuermann after a new task force was created to investigate the cold case in 2021.

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Police discovered the four women's remains while searching for another missing woman, Shannan Gilbert, who vanished after calling 911 in a neighboring beach community on the same parkway. Six other bodies were also recovered nearby.

The discovery process is ongoing. Heuermann is due back in court on Nov. 15. He faces up to life imprisonment without the possibility of parole if convicted.

In the meantime, he is being held without bail at the Suffolk County Jail in Yaphank.

Fox News' Angela Bertorelli contributed to this report.