The SWAT series are the follow up of Sierra's classic adventure game series Police Quest. The adventure game decreased in popularity by the mid-nineties and Jim Walls, the former series designer, left Sierra and was replaced by real-life SWAT founder Daryl F. Gates. After Gates released Open Season, Sierra searched out new genres for the popular police simulation series. SWAT and SWAT 2 were fifth and sixth games of Police Quest series, before the Police Quest title was dropped in the later SWAT games. SWAT 3 was later rereleased as part of the Police Quest: SWAT Generation compilation.