SAN FRANCISCO (KGO) -- A San Francisco sheriff's deputy has been convicted of assault Tuesday of an attack that happened last November.Michael Lewelling arrested a man at San Francisco General Hospital and claimed the man attacked him with a cane.Investigators say video evidence shows him choking the man before arresting him.Prosecutors accused him of lying on the police report, saying he was attacked by the patient first.Lewelling faces a maximum three years in state prison.