The search is going back to Suffolk County.

State Police, who examined a stretch of the Wantagh State Parkway in Nassau Monday and did not find any human remains, said that they will canvass the southern portion of the Robert Moses Causeway Tuesday.

The search, which is to begin about 8:30 a.m., will stretch from Ocean Parkway to the southern end of the main-span bridge.

Monday's examination, which was the first off the barrier island where Shannan Gilbert, 24, last was seen a year ago, did not yield any remains, authorities said.

State Police, with the Nassau police, state park police and State Environmental Conservation police, combed through both sides of the Wantagh from Merrick Road to Ocean Parkway.

The disappearance of Gilbert, who authorities said worked as a prostitute, triggered what has become one of the largest police investigations in Suffolk County history, an ongoing search that has uncovered as many as 10 sets of human remains in Suffolk and Nassau counties.

Police have said that the first four sets of remains found -- all women who had worked as prostitutes -- may be the work of a serial killer. The other sets of remains, four others found in Suffolk and a skull and a bag of bones found in Nassau, have yet to be identified.

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Tuesday, the Robert Moses Causeway from Montauk Highway to the Ocean Parkway will be closed for an indeterminate amount of time, said State Police Capt. James Dewar.

Commuters can access Captree and Robert Moses state parks from Ocean Parkway while the search takes place.

Suffolk police, state park police and State Environmental Conservation police will help State Police in Tuesday's canvass.

Since December, police have conducted several canvasses of the area to look for Gilbert, a prostitute from Jersey City who last was seen alive May 1, 2010, in Oak Beach. Gilbert remains missing. Of the remains found, only four have been identified: Maureen Brainard-Barnes, 25, of Norwich, Conn.; Melissa Barthelemy, 24, of the Bronx; Megan Waterman, 22, of Scarborough, Maine; and Amber Lynn Costello, 27, of North Babylon.

Forensic experts are working to identify the others, police said.

With Matthew Chayes