A DNA sample taken from Rex Heuermann, charged with three of the so-called "Gilgo four" murders on Long Island in New York matched DNA previously used to link him to one of the killings, prosecutors said Wednesday.

Heuermann, 60, was arrested in July after investigators matched DNA from a pizza crust he had tossed with DNA from a male hair found in the burlap used to wrap the body of Megan Waterman. He is charged with the murders of 22-year-old Waterman, 24-year-old Melissa Barthelemy and 27-year-old Amber Costello, and is a prime suspect in the death of a fourth woman, 25-year-old Maureen Brainard-Barnes.

The bodies of the women, who authorities say were sex workers, were found in 2010 on Ocean Parkway in Gilgo Beach. A total of 10 sets of human remains have been found buried in the area, though the majority of cases remain unsolved and investigators don't think one person committed all the killings. Investigators do believe a serial killer is responsible for some of them.

Prosecutors confirmed during a short pretrial court appearance on Wednesday that a court-ordered swab taken directly from Heuermann's mouth matches the DNA from the pizza.

"The buccal swab erases all doubt,” District Attorney Ray Tierney said in court, according to CNN.

Defense attorney Michael Brown said outside court that the DNA found with the victim's body could still belong to someone else.

“It’s still a significant amount of people that could be the source of this hair,” Brown said, according to CNN.

Heuermann, who worked as an architect, said in court Wednesday that he has been reviewing evidence in his case and been averaging two or three hours a day of review time while in jail.

He has pleaded not guilty to the murders and is being held without bail.

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What's next in the case?

Prosecutors said they will continue providing massive amounts of evidence in the case ahead of Heuermann's trial.

They have previously said they have given Heuermann’s lawyer thousands of pages of records, DNA reports and about 100 hours of surveillance video recorded outside Heuermann’s home and office before his July 13 arrest, along with crime scene photos – and warned there's a lot more coming.

“You’re talking about 13 years worth of investigation,” Tierney previously said.

He's expected back in court in November for another status hearing, CNN reported.

TIMELINE:What led to arrest of suspect Rex Heuermann in Long Island

Contributing: The Associated Press