Police comb the waters of an estuary in Oakland, searching for the gun used in a shooting spree that killed seven people earlier this week.
Authorities are using police divers and boats equipped with sonar technology to aid in the search.
The suspect in the shootings at a small Christian college in Oakland is 43-year-old One Goh.
He stands charged with murder and attempted murder.
The former student at Oikos University is accused of opening fire on former classmates and staff, in the deadliest gun violence at a U.S. college since a Virginia Tech student killed 32 people in 2007.
The motive for this week's shooting remains unclear, but police said Goh had "anger management" issues.
Travis Brecher, Reuters
