"Police Quest IV differs significantly from the first three games, in both game engine and story. The player plays the character of homicide detective John Carey, rather than officer Sonny Bonds, and the game is set in Los Angeles, California rather than the fictional Lytton. Backgrounds for the game are scanned photographs rather than painted scenery, and depict real locations in Los Angeles. The Parker Center is a location used in the game, and is virtually unchanged from when the game was made. Written text is replaced by audible narration and dialogues on the CD version, released in 1996.
The entire game, like Police Quest III and the 1991 re-make of Police Quest 1, is based on a mouse-controlled user-interface system. Icons such as "walk", "speak to", "touch", "use", and "look at" are used rather than the old-fashioned text-parsing system used in the first two games.
Homages to Sonny Bonds appear in two places, the name of the police server is "SONNY" and "Sonny Bonds" also appears on the high score screens of the two arcade games in the Short Stop."
Source: Wikipedia, "Police_Quest:_Open_Season," available under the CC-BY-SA License.