RIVERHEAD, N.Y. (NewsNation) — Gilgo Beach murder suspect Rex Heuermann continues to maintain his innocence in connection to the killing of three women along the New York coast, but DNA is only adding to the evidence against him, according to prosecutors.

Genetic material taken from Heuermann’s cheek swab matches what authorities had previously collected from a pizza crust and used to link the 60-year-old suspect to one of the victims, prosecutors said Wednesday.

Heuermann was arrested July 13 on murder charges in the killings of Melissa Barthelemy, Megan Waterman and Amber Lynn Costello, three of the women whose bodies were found along a remote beach highway on Long Island, and has been named as the prime suspect in the death of a fourth woman.

He pleaded not guilty and has been held without bail at a Suffolk County jail in Riverhead.

At the time of his arrest, prosecutors said they had analyzed DNA from a pizza crust that Heuermann had discarded in a Manhattan trash can and matched it to DNA from hairs found on Waterman’s body. Prosecutors then got permission from the court to collect DNA from a cheek swab of Heuermann as further proof of his link to Waterman’s killing.

“The buccal swab erases all doubt,” Suffolk County District Attorney Ray Tierney told the judge, according to Newsday.

Heuermann’s lawyer disputed the significance of the DNA sample.

“There is nobody on the face of the earth that is credible is going to say that hair is my client’s hair,” defense attorney Michael Brown said outside the courtroom.

The arrest of Heuermann, an architect, came 13 years after police searching for a missing woman found 10 sets of human remains buried in the scrub near Long Island’s remote Gilgo Beach.

The Associated Press contributed to this report.