Barry Crouch???

My answer is, regrettably, toolong to post here. Please read "Barty Crouch and the Triwizard Tournament" for my full answer.

i dunno

Barty Crouch Jr. tortured Frank and Alice Longbottom with Bellatrix and co. They were caught and sent to Azkaban. I'm not sure whether the screaming was an act or not. Anyway, his mother was dying and her last wish was to save her son, who was also dying. Crouch Sr. and his wife rescued Barty and Mrs. Crouch died in Azkaban. Barty was hidden by his father, until Voldemort heard of him through Bertha Jorkins, who had seen Winky talking to Barty. At the Quidditch World Cup, Barty, was able to think clearly enough to steal Harry's wand and cast the Dark Mark. Soon after Voldemort rescued Barty and Mr. Crouch was Imperioused. Barty impersonated Mad-Eye and pretty much loaded the dice in Harry's favor. He doctored the Cup to take Harry and accidentally Cedric to the graveyard and when Harry returned tried to kill Harry. That's it, in a nutshell.