Suffolk police said Friday that Shannan Gilbert's remains may be in one of the drainage canals that line the nearly 100-acre marshland in Oak Beach and officers will return on Monday to try to find her.
It's possible for a person to step into a trench and "be suddenly waist deep" in water, Suffolk Insp. Stuart Cameron said Friday, elaborating on the police theory that Gilbert may have drowned.
"We brought in an excavator and we're digging them out with the possible assumption that she may have fallen in there and is now below the surface," Cameron said.
The trenches were dug in the late 1990s and have been filled with silt to become like quicksand or covered over with vegetation.
During Friday's search -- the fourth consecutive day at Oak Beach -- police said they found lip gloss within a few feet of where they had found a pocketbook identified as belonging to Gilbert. They suspect the lip gloss is hers, too.
The 24-year-old Jersey City, N.J., woman who worked as a prostitute disappeared on May 1, 2010, after she saw a client in Oak Beach. A search for her last December led to the eventual discovery of 10 victims.
The lip gloss and the pocketbook were found hundreds of feet from Anchor Way, a north-south road that separates several houses from the marshland, Cameron said after the day's search ended.
Police this week also turned up shoes, a cellphone and a pair of tattered jeans Gilbert was believed to have been wearing on the night she disappeared.
They have said the items recovered and their locations are indicative of a person running wildly into a marshy area in the dark. Police and witnesses have said Gilbert ran frantically from the client's house to a neighbor's house in the beachfront community, yelling for help but never making clear why. Then she took off again toward the brush.
Gilbert's family and others have questioned why her remains weren't found in the tattered jeans police recovered.
"If she had died with the jeans on her and the body deteriorated postmortem, there would have been some evidence of skeletal remains," said Dr. Michael Baden, a former New York City medical examiner. "The bones don't just disappear."
Det. Lt. Gerard Pelkofsky said Suffolk police believe animals may have ripped the jeans off Gilbert's body.
On Friday, officers with metal detectors and search dogs combed different parts of the marsh and uncleared brush near the gated Oak Beach community. The method was unlike Thursday, when they used heavy machinery to dig in one area.