Oakley resident Stephen Paul Clark, 45, a registered sex offender, is suspected of kidnapping and raping a 43-year-old woman in Oakley on Saturday night after meeting her at a local establishment, according to the sheriff's office.
California Highway Patrol officers spotted Clark in San Diego County on Wednesday, but he ran away and has not been seen since, sheriff's spokesman Jimmy Lee said.
Local, state and federal authorities have been alerted that Clark is wanted.
Police said Clark has been convicted of rape in Texas and is considered armed and dangerous.
Anyone with information about Clark or his whereabouts is urged to contact the sheriff's office sexual assault unit at (925) 383-4942.