Who are they? Where do they come from? Why do they do it? Serial killers are the headline-grabbing criminals of the modern world. With the body count rising, and shallow graves giving up their secrets, almost weekly new names join the list of terrifying murderers, already swollen with the 20th century's most notorious and fearsome criminals. Here are the full stories behind all the most infamous thrill killers: Jeffrey Dahmer, the monster of Milwaukee; Dennis Nilsen, who killed for company; Richard Ramirez, the Night Stalker; Ian Brady and Myra Hindley, the Moors Murderers; Beverly Allitt; the Yorkshire Ripper and many more ..