What makes a serial killer tick? Are there any common characteristics these homicidal criminals share with one another? The life of a serial killer is something that usually intrigues and disturbs people in equal measure. Trying to understand how a person could be compelled to keep on murdering others for the sheer pleasure of it is just one aspect of what a criminal psychologist does for a living. Find out some interesting statistics and chilling facts about the behaviour of serial killers in this eye-opening infographic.