In 2002, a sniper terrorizes Washington D.C. and the surrounding suburbs, randomly targeting ordinary citizens. Ten are killed, three wounded.

In 1980, the entire world was stunned by the murder of John Lennon. Was Mark Chapman a cold-blooded killer or a seriously deranged young man? We will backtrack through the lives of both men to set the scene through interviews and footage.

What drove a Texas mom to do the unthinkable and drown her five small children in the bathtub of their Houston home?

In 1981, a gunman fires six shots at Ronald Reagan. What follows is a chaotic rush to save Reagan's life, confusion at the White House, and an urgent investigation to find out if this is a wider plot, or the work of a lone assassin.

In 1995, in an Oklahoma City federal building, a truck bomb killed 168 people. What caused a decorated war hero to carry out this attack?

In 2007, Amanda Knox, a US student living in Italy, was arrested for the murder of her roommate.