The Police Quest series are traditional adventure games developed by Sierra which follow the adventures of Sonny Bonds, a police officer in the fictional city of Lytton, California, designed under the supervision of former Highway Patrol officer Jim Walls. The last game in the series are a departure from the first three, and follow the murder investigations in real-life Los Angeles led by detective John Carey. Jim Walls was replaced by former LAPD Chief Daryl F. Gates. The adventure games were discontinued after the fourth game, but Sierra continued to publish "police simulators" under the brand name SWAT