Serial killers are often twisted geniuses; so cunning that catching them seems almost impossible. But from Jack The Ripper to those who terrify us today, their bizarre behavior is as specific as a signature. Sophisticated crime fighters map the psychological and physical terrain of multiple murderers.

Weapons are the hallmark of violent crime, tools designed to harm - or kill. Forensic science has developed a world of techniques for tracking and identifying these devices. Blood spatter, explosive residue, ballistics and trauma wounds tell crime scene investigators their deadly story.