"Billy Loomis" is "Sidney's" boyfriend throughout the film. After they received the killer's call, "Billy" was arrested because he was supposedly in possession of the phone presumably used to call his victims. However, he was released due to the lack of evidence supporting the police's claim. At the party, he sleeps with "Sidney" and is then allegedly stabbed by "Ghostface". As "Sidney" comes back into the House, the wounded "Billy" comes stumbling down the staircase. Ultimately, "Sidney" discovers that 'Billy' was really one of the killers all along. They wanted to pin the evidence on "Sidney's" father, who allegedly went crazy on the day of his wife's death . "Billy" is also responsible for the murder of "Sidney's" mother due to the affair "Billy's" father was having with "Sidney's" mother which led to the divorce of "Billy's" parents.