SMITHTOWN, N.Y. – A missing prostitute from New Jersey was not among the four women whose bodies were found in the past week on a deserted waterfront highway in New York, detectives said Thursday.

Investigators believe a serial killer could be responsible for the deaths. None of the remains are those of Shannon Gilbert, 24, who was reported missing in May, said Suffolk County Police.

Police discovered the first of the four bodies Saturday while investigating Gilbert’s disappearance. The other three were found within a quarter-mile of each other on Monday.

Suspicion that Gilbert was among the victims was sparked by revelations that she was last seen in a private community about three miles from where the bodies were found.

A man who is believed to be among the last people to see Gilbert voluntarily surrendered his SUV to detectives as part of their investigation. Police never identified the man, or anyone else, as a suspect in Gilbert’s disappearance or the four deaths.

The man, Joseph Brewer, owns a house in Oak Beach, near where the bodies were found. He said Thursday that officers had asked him not to say whether his SUV had been returned.

“They have been very generous. And I have been cooperative, too,” he said.

“There’s four families missing their four young girls; those are the true victims. I feel sorry for them,” he said.

Authorities have obtained a DNA sample from the mother of a missing Maine woman who was last seen working as an escort on Long Island.

Megan Waterman of Scarborough, who advertised escort services online on Craigslist, was last seen in June at a hotel in Hauppauge, N.Y., about 15 miles from where the bodies were found.

Suffolk County Police Commissioner Richard Dormer has said that it could be days or weeks before the bodies are identified. The New York City medical examiner’s office is assisting with identification.

Dormer sought to calm fears during a briefing Thursday.

“I don’t want anybody to think we have a Jack the Ripper running around Suffolk County,” he said. “I would say to people, go about your business.”

Detectives believe the four women were killed elsewhere and then taken to the site, a narrow strip of land that divides Great South Bay from the Atlantic Ocean. A parkway runs through the middle.

On Thursday, officers and 10 state police dogs expanded their search of more than 10 miles of the Ocean Parkway, where the bodies were found. “We want to make sure that we didn’t miss anything,” Dormer said.