Plot synopsis: This true-crime series takes a look at what happens when someone goes on a killing spree. `Killing Spree' tells the story behind the killings, using first-hand accounts from the people involved - including officers who investigate the crimes - and those who knew the perpetrators in addition to forensic evidence behind the crimes.to help explain what causes the people responsible for the killings to commit the crimes. The programme also examines the life and character of the perpetrators to provide viewers with insight into their complex lives.