Emily Sullivan was a villainess from "Mean", episode 5.17 of Law & Order: SVU (airdate February 24, 2004). She was a popular student at Tanner Day Academy and the leader of a clique of three other girls: Brittany O'Malley, Andrea Kent, and Paige Summerbee. Emily was found brutally murdered in the episode's beginning, with her corpse being found in a car trunk.
As the SVU detectives investigated Emily's murder, they discovered that in life, Emily had been a vicious bully, as documented through her various abusive text messages to fellow Tanner Day student Agnes Linsky. It was also revealed that Emily's other friends were also bullies, with Agnes being their most targeted victim, and the principal did nothing to stop them due to their status as the school's most popular students. Agnes recounted for detective Olivia Benson Emily's numerous callous acts against her, including pretending to be her friend several times just to hurt her and spreading rumors that her deceased mother actually left because of how ugly she was.
It was ultimately discovered that Emily had been killed by Brittany, with Andrea and Paige assisting her in the brutal murder. As a test of her friendship to Emily, Brittany sent her boyfriend Lukas Ian Croft to start dating Emily. When Emily continued the relationship, Brittany decided to kill Emily, kidnapping her one night after luring her out of her house and putting her in the trunk of her car after tying her up with duct tape. After driving around for a while, Brittany viciously attacked the bound Emily, burning her with cigarettes and cutting her with manicure scissors before stabbing her villainous friend to death with a knife.