From Wikipedia: SWAT 4 is a tactical first-person shooter computer game developed by Irrational Games and published by Vivendi Universal Games on April 5, 2005. It was built on Irrational Games's Vengeance engine powered by Unreal Engine 2.0 technology. In SWAT 4, the player leads a SWAT tactical element in resolving various situations, such as hostage standoffs or apprehensions of dangerous subjects. An expansion to SWAT 4, entitled SWAT 4: The Stetchkov Syndicate, was released on February 28, 2006.