Before the collapse of Rapture's society, internal security was mainly handled by a police force headed by Andrew Ryan's lieutenant, Sullivan. With Sullivan having resigned, and the police force in shambles (with some of its remnants joining the Splicer forces scavenging the city), the automated security forces were left with the duty to guard what remained of the city. Security in Rapture revolves around a three-pronged approach with cameras as constant surveillance, automated static defenses as sentries, and automated mobile units as enforcers which travel to the location of disturbances. Major enemies have shown some degree of control over the security system, as a few Splicers have been able to turn these defenses to their advantage by hacking, and even set them up in the players path.