Investigators with the Modesto Police and the Tuolumne County Sheriffs departments were searching the San Francisco Bay Wednesday in the Laci Peterson case.
Police would not say what led them to their third trip to the Bay in the three-month-old investigation.
"This should not indicate there is a significant change in the case or a break in the case," said Detective Doug Ridenour, spokesman for the Police Department.
Three boats from the Tuolumne County Sheriff's Department were searching an area off of Richmond Point, a few miles north of the Berkeley Marina.
Divers first searched the waters off the Berkeley Marina in January. Scott Peterson told police he had been fishing there on Christmas Eve, the day his wife disappered.
Last week, police reclassified the case as a homicide investigation.