Operating in New York City during the late seventies, this killer  appeared as an extra in the 1973 movie "The Exorcist".

Known as BTK, he really did work for ADT.

He was one of three men who were responsible for the "Houston Mass Murders".  He confessed to procuring victims for the ringleader who was known as "The Candy Man", after killing him in self defense.

How did William Junior Pierce and William Henry Hance differ from the other serial killers that the team interviewed, causing them to re-evaluate their profile theories?

Known as the Co-Ed Killer, he was a real (dead) M*ther F*%#r

Committed to a psychiatric hospital for rape at the age of 14, this teenage serial rapist and killer snuck out and raped an additional 5 women while institutionalized. By the time he was caught, in 1977 he had raped and killed five more women near his home in Alexandria VA

This crying killer from Altoona was fictional, though the murder was based on a true story they changed the names.

On July 14, 1996 he brutally murdered 8 nursing students on Chicago's south side. In prison he was given the nickname "Birdman" because he kept a pair of sparrows in his cell.
In a video released in 1996, five years after his death, it clearly showed that he had somehow managed to grow a pair of breasts, making him very popular with other inmates.

Known as the lust killer, at the age of 5, he found a pair of stiletto heels in a junkyard, but his mom took them away. In the series he claimed that his victims came with him willingly to his garage to be photographed, but in truth, he abducted his victims at gunpoint or used force to get them there.

Before he was known as the "Son of Sam" David Berkowitz was known as