'Michael Douglas' quit the show in 1975 to produce One Flew Over the Cuckoo's Nest (1975). His character's absence was explained by having him take a teaching position. In the San Francisco police department, an "Inspector" is just a detective rank. In other police departments, an Inspector is a much higher rank (in the NYPD, Inspector is the rank above Captain; in the UK police, an Inspector is equivalent to a Lieutenant).