and The Associated Press

Divers searched Lake Tulloch as well as other rural lakes Sunday morning for 27-year-old Laci Peterson of Modesto, missing since Christmas Eve.

Saturday, more than 40 investigators and 16 "cadaver dogs" searched rural areas and waterways in Tuolumne, Calaveras, San Joaquin, Merced and Mariposa counties, Modesto Police Sgt. Ron Cloward said.

Cadaver dogs are often used in searches because they can pick up scents even in the water, said Tuolumne County Sheriff's Department Lt. John Steely.

Steely declined to comment on whether the dogs picked up scents in Lake Tulloch, but said divers from Calaveras and Stanislaus County Sheriff's departments were in the water Sunday morning and did not find any bodies, Steely said.

Laci Peterson is 8 1/2 months pregnant. Her husband, Scott, told police he spent Christmas Eve day at Berkeley Marina, and when he returned, she was gone.

Dogs and divers also searched the Berkeley Marina, Cloward said.

There are no suspects in Laci Peterson's disappearance, police said, and investigators have been trying to corroborate Scott Peterson's whereabouts to clear him.

Scott Peterson said he last saw his wife about 9:30 a.m. Dec. 24. He told police she planned to take their dog, McKenzie, for a walk at nearby East La Loma Park.

Peterson said he left that morning to fish in San Francisco Bay on Christmas Eve, launching his small boat from the Berkeley Marina.

Cloward said police searched the shallow Berkeley Marina this weekend because the clear weather finally gave them the opportunity.

''We have to eliminate all these possibilities. And until I'm satisfied that we've eliminated the possibility that she's in a bay, a creek, a river or a lake, I'm not going to be satisfied,'' he said.

Cloward said the command post for the search would be moved Monday from a park near the Petersons' Modesto home to the police station.

The area near the house has been searched numerous times and ''we're at a point now where we've covered that area,'' Cloward said.

Police have received more than 1,100 tips through a hot line. A reward for Laci Peterson's safe return has grown to $500,000.

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