Serial Killers in the U.S Before we can discuss what serial killers do, we must first define what a serial killer is. Some people might place serial killers into the same group as mass murderers. This would be incorrect because they are two totally different types of killers. While both of these individuals may kill many people, the difference lies in the reason they kill and the period over which they kill their victims. An event or a build up of circumstance triggers mass murderers and causes them to act. This may be the result of a stressful situation or frustration either at work or in their private lives. For whatever reason, they may