Professor of the criminal mind and the world's foremost authority on murderers, Philip Carlo delved into the psyche of serial killers. Violent crime and serial killings have occurred since the dawn of man, he said. According to Carlo, werewolf and vampire folklore was created as a way to help explain murders so gruesome and brutal that people could not imagine a human being having committed them. Carlo talked about the BTK (Bind, Torture and Kill) strangler, Dennis Rader, whose murderous rampage lasted for 40 years. He described Rader as a sexual sadist, and pointed out that serial killers as a group are motivated by sexual sadism to commit their horrendous crimes. Carlo believes part of what makes a serial killer want to do what they do is having endured severe physical and mental abuse during their formative years. Carlo commented on Richard Ramirez, aka 'The Night Stalker,' who terrorized the nighttime streets of Los Angeles in the mid-80s, raping and killing women and their husbands. In 1992, Carlo interviewed Ramirez for a book he was writing about the infamous killer. Ramirez was polite, funny and gentleman-like, Carlo explained, surprised at how "grounded" the killer came across. Despite their violent nature, serial killers fit in with the rest of us, he said. This duality is what Carlo finds most fascinating about serial killers. Carlo estimated that at any given time there are about 500 serial killers roaming the US He also talked about mafia contract killer ...