Introduction: The term serial killer was coined in the 1970s by a man named Robert Ressler. He chose the name serial killer to describe a killer who murders three or more victims over a period of time because the FBI was always investigating a series of cases created by the killers (Freeman, 2007). Serial killers have been around for centuries, since ancient times. Many studies have been done to try to understand how the minds of serial killers work, so that the FBI can catch them and find a way to stop them. Not all serial killers are the same, so it is difficult to understand them and provide a clear definition of how their minds work. Most serial killers have similar character traits and can be classified into different categories to make it easier to find patterns and reasons for why they kill. Early Indicators of a Person Becoming a Serial Killer: In 1963, JM MacDonald compiled a list of attributes. /characteristics that are now considered early indicators of violence; this list was later called the MacDonald Triad. These characteristics include fire-setting, animal cruelty, and enuresis; These traits are often first noticed when they are children. Fire lighting often begins with the child's curiosity about what happens when you light a fire, but then it becomes a way for the child to deal with stress and anger. It is an act of “speaking out” because the child feels like no one is listening and wants attention. This characteristic/behavior could become more dangerous if the child continues to feel the need to relieve stress/anger by starting fires, as the child will begin to start larger fires and experiment with fires more. Animal cruelty is another major factor in MacDonald's triad; it is ...... middle of paper ...... violent behavior: myth or reality? SerialKillerLab. Accessed March 28, 2014, http://serialkillerlab.blogspot.ca/2013/04/macdonald-triad-as-predictor-of-violent.htmlCharney-Perez, J. (April 1, 2005). "History of serial killers". Serial killers. Accessed April 23, 2014, http://iml.jou.ufl.edu/projects/spring05/charney-perez/history.htm “Macdonald Triad.” Sociopathology. Accessed April 14, 2014, http://sociopathology.org/tag/macdonald-triad/Scott, SL “What Motivates Serial Killers?” Crime Library. Accessed April 3, 2014, http://www.crimelibrary.com/serial_killers/notorious/tick/victims_1.htmlDee, C. (2007). Serial killers, up close and personal: inside the world of torturers, psychopaths and murderers. Berkeley, CA: Ulysses Press. Roland, P. (2006). The Crimes of Jack the Ripper. London: Arcturus.