Most serial killers are sexual psychopaths or psychopathic sexual sadists, depending on the circumstances of the homicide and what was done to the victim. Although they have a profound personality disorder, they execute their crimes rationally and may succeed in living apparently "normal" lives when not hunting or killing victims. Serial killers kill to fulfill an emotional need for power and control over others. The fulfillment of sexual fantasies is a secondary aim. They select victims who are vulnerable and easy to manipulate. They often use charm and appeal to victims' charitable instincts to maneuver them to a private location where they can gain physical control over them. Following their murders, they can be meticulous, as was Ted Bundy, in removing crime scene evidence and obstructing victim identification. They typically enjoy demonstrating that their power to avoid detection is greater than the power of the police to catch them. They tend to follow media accounts of their crimes and vary their operation according to police perceptions of their methods. They profit from the failure of police agencies to communicate across jurisdictions.