Police reported no new findings Thursday after searchers used heavy machinery to dig through an Oak Beach marsh they said may hold the remains of a woman working as an escort the night she disappeared last year.

After looking for a third straight day in an area north of a gated community where Shannan Gilbert, 24, of Jersey City, was last seen on May 1, 2010, Suffolk County investigators ended the search just before sundown.

Police are expected to resume their work at 8 a.m. Friday.

Gilbert was last seen running from the Oak Beach home of a man who had answered her ad on Craigslist, police said. Her disappearance spawned an unprecedented search along Ocean Parkway that led to the startling discovery of 10 sets of remains -- eight women, one toddler and a man dressed in women's clothing -- between Dec. 11, 2010, and April 11.

Police believe the victims are the work of one serial killer, though they believe Gilbert's disappearance is not related.

Suffolk County Police Chief of Detectives Dominick Varrone had said earlier that detectives close to the case believed Gilbert was not murdered, but rather may have run wildly into the marshy area in the dark and drowned.

Late Thursday morning, plywood planks were laid over part of the marsh to allow a small digger to excavate the area. An amphibious vehicle trundled through brush about 300 to 500 yards east.

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A Suffolk County police helicopter flew over the search area shortly before 8 a.m. as crime scene and homicide detectives gathered, along with workers from Suffolk's vector control department.

On Tuesday, searchers had combed the marshy brush and found a pair of tattered jeans, ballet-style flat shoes and a pocketbook containing Gilbert's ID. On Wednesday, crews located a cellphone believed to be Gilbert's, police, officials said.

With John Valenti, Emily C. Dooley and Chau Lam