The unidentified diver told the sheriff's office that he saw what looked like human remains in 95 feet of water near the Lake Sonoma bridge.
Sonoma County sheriff's deputies, the Marin County sheriff's dive team and an underwater robot from the Oakland Police Department started searching the lake at about 8 a.m. today.
In a separate case, authorities are investigating the discovery of a human skull and a tennis shoe that were found in a creek bed in Shiloh Range Regional Park near Windsor on Sunday.
