Jeffrey Dahmer. Ted Bundy. David Berkowitz. Aside from killing dozens of innocent people (combined), these menand a significant percentage of other serial killershave something else in common: Years before turning their rage on human beings, they practiced on animals. According to the FBI, animal abuse is highly correlated with interpersonal, human-to-human violence. Serial killers often torture or kill small animals from an early age, and men who commit child abuse or domestic violence very frequently harm household pets as well. If somebody is harming an animal, there is a good chance theyre also hurting a human, said John Thompson, deputy executive director of the National Sheriffs Association, in a 2016 interview.