Among the most disturbing crimes are those committed by serial killers. These heinous criminals, sometimes known by lurid nicknames like the Boston Strangler, Dusseldorf Vampire (Peter Kurten), Monster of Florence (Mary Ann Nichols), and John Wayne Gacy, brutally murder several people at one time in order to fulfill some kind of sick psychological gratification. Their murders have caused the public to be both fascinated and horrified, and they raise numerous social and legal issues.

For decades, filmmakers have attempted to capture the essence of these killers in movies that not only titillate, but also challenge the viewer’s notions of what is acceptable, and what is not. While most of these films are merely sensational and gruesome, the best examine how society may contribute to serial killings.

Although fewer than 1% of all deaths in a given year, serial killings seem to be on everyone’s mind. TV shows like Dexter, Criminal Minds and the new Hannibal appear to be obsessed with finding out what makes a killer tick – is it a childhood event that leads to murder, or is there some element in a person’s psychology that goes terribly wrong?

While many theories have been advanced on what causes a person to become a serial killer, Symposium attendees agreed that there is not one single identifiable cause. A person’s development from birth to adulthood is influenced by a wide range of factors, including heredity, upbringing, life events and choices that occur throughout their lifetime, as well as certain biological characteristics.

A central discussion point was the definition of what constitutes a serial killer. Most symposium attendees favored a definition that included two or more killings of a similar nature, with no discernible cooling-off period between them. A few attendees suggested that motivation be included in the definition, but most felt it should not, as this would complicate matters and make it difficult for law enforcement to identify serial killers.

The question of whether spree murder should be considered a separate category was also a topic of debate. Most attendees felt that this designation was unnecessary and did not provide any real value to law enforcement.

Most serial killers will only kill within a fairly limited geographic area, often defined by an anchor point such as their place of residence or work location. Some, such as Ted Bundy, will occasionally spiral their murders outside of this comfort zone, but only when they feel more confident in their ability to avoid detection.

Those who live an itinerant lifestyle, such as truck drivers or military personnel, are more likely to have multiple zones of comfort in which they will kill. However, these individuals tend to be less effective at avoiding detection because they are frequently confronted with a lack of police communication when they travel between jurisdictions.