School mass murder shootings were practically unheard of prior to the 1980s. It is the purpose of this qualitative case study to explore what parents of teenagers believe are shared behaviors, social characteristics and personality traits of juveniles at risk of becoming mass murderer offenders. Being a loner or having social isolation was the primary characteristic determined by the parents. Psychiatric disorders, being angry, and being bullied were also named by over half of the parents. The primary information source that the parents said they obtained this information from was from the news media. This information did not match the information provided by the literature review. Being a loner and having psychiatric disorders are not characteristics of a juvenile contemplating mass murder.