The USA has 76 percent of the world's serial killers. During the 1980s, FBI special agents traveled around the country to conduct death row interviews with 198 of them. The FBI agents from Quantico gained valuable insights into a predator's mindset. This information formed the basis of a new field of study called behavioral profiling.

This face-to-face research continues today. Thousands of serial rapists and sexual murderers have disclosed tricks of the trade to criminal profilers and forensic psychiatrists. But what the professionals discovered about their modus operandi has...