The Night Stalker - Delroy Grant: With a reign of terror that spanned almost 20 years, Delroy Grant was one of the UK's worst rapists. Nicknamed "The Night Stalker," he would sneak into the homes of the elderly and assault them before disappearing into the night. He went undetected for many years due in part to mistakes made by the police, but in 2009 a restructuring of the investigative process put them hot on his trail.