Posted by on February 11, 2017
Categories: Bay Area


(BANT) – A medical assistant who was arrested Friday morning after he allegedly sexually assaulted a woman at a Kaiser permanent medical office in Union City last month has been identified.

Officers arrested 47-year-old Hayward resident Efrain Castanon on suspicion of sexual assault, Lt. Jeff Snell said.

The victim told police that during an appointment on Jan. 25 at the Kaiser Permanent Union City Medical Offices on Whipple Avenue, a medical assistant sexually assaulted her, according to police.

Officers were ultimately able to identify Castanon as the suspect.

During the investigation, police said Kaiser Permanente officials were extremely cooperative.

According to court records, Castanon is scheduled to appear in Alameda County court on Tuesday.

Anyone with information about the case or who believes they may have been victimized in a similar manner is asked to call Detective Ryan Seto at (510) 675-5266. Information can also be left anonymously at (510) 675-5207
or at