The killers in Scream 4 are Jill Roberts and Charlie Walker. Jill is Sidney Prescott's cousin and is motivated by jealousy and a desire for fame, wanting to be the "sole survivor" and gain clout similar to Sidney. Charlie, Jill's high school friend and romantic interest, is interested in recreating the terror caused by the original killers. Jill ultimately betrays Charlie, kills their victims, and attempts to frame others to achieve her goal of fame. The two work together but Jill is the mastermind behind the murders, using a combination of knives and guns as weapons.
