Pizza played a decisive role in the identification of a suspected serial killer arrested on Long Island, New York, according to news reports.

Authorities arrested Rex Heuermann, a New York architect, on Thursday night, July 13, and charged him with six counts of murder. The arrest is in connection with the murder of three women whose bodies were wrapped in burlap material and discovered along Long Island’s Gilgo Beach in 2010. Other bodies—at least 10—were also found in the area, according to CBS News.

Heuermann has denied the charges and entered a not-guilty plea at his arraignment. He has been charged with three counts of first-degree murder and three counts of second-degree murder in the deaths of Melissa Barthelemy, Megan Waterman and Amber Costello. He’s also the prime suspect in the disappearance and death of Maureen Brainard-Barnes but has not yet been charged with that murder.

The murders went unsolved for years until the Suffolk County police commissioner put together a multiagency task force to investigate them. As CNN has reported, a discarded pizza box and pizza crust figured into the detective work.

Related: Who are the country’s leading pizza influencers for 2023?

For starters, prosecutors say, Heuermann used Barthelemy’s cell phone to call and taunt her family members and admitted to sexually assaulting and murdering her. Investigators used phone records from cell towers to narrow down the location of the suspect. They looked for a person who matched a physical description of the suspect provided by a witness who had seen the alleged killer. A witness also reported the suspect drove a green pickup truck, CNN reported.

After determining that Heuermann matched the witness’s physical description of the suspect and lived and worked in the area being investigated, they also learned that he drove a pickup truck that had been seen by witnesses in the vicinity.

With a suspect identified, authorities began using DNA evidence found in hairs left on victim Megan Waterman’s body. Some of those hairs were determined to come from another female, not the victim.

Using bottles left outside Heuermann’s home for trash collection, investigators obtained a DNA sample that’s believed to belong to Heuermann’s wife, according to NBC News. Analysis allegedly matched it to the DNA found on the woman’s body. But police had determined that Heuermann’s wife was out of town when the various murders occurred.

Related: This small chain aims to recapture Pizza Hut’s glory days

A male hair was also found on the burlap in which Waterman’s body had been wrapped. To get a direct DNA match, a surveillance team recovered a pizza box Heuermann had thrown into the trash. Authorities were able to collect and test a DNA sample from the leftover pizza crust in the box to establish a possible match between Heuermann and the DNA found on the burlap that contained Waterman’s remains.

According to a Suffolk County District Attorney’s court document in the case, the DNA found on the male hair and the pizza crust have the “same” mitochondrial profile, excluding 99.96% of the North American population.

Based on those lab results, investigators said it’s “significant that Defendant Heuermann cannot be excluded from the male hair recovered” from the burlap used in Waterman’s murder.