San Francisco police have arrested an election worker but have not recovered 75 ballots he allegedly stole from a polling station, police said Wednesday.

Karl Bradfield Nicholas, 50, of San Francisco left his post at 4:15 p.m. on election day at the station on Knott Court with the ballots and a memory card that recorded the votes cast, said Lt. Lyn Tomioka, a San Francisco police spokeswoman.