A 15-year-old girl committed suicide after three boys allegedly sexually assaulted her and circulated photos of the abuse online.
Audrie Pott hanged herself a week after passing out drunk at a party at a friend's house in Saratoga, Northern California, while the parents were out of town.
She claimed the boys, whom she had known for years, took off her clothes and sexually assaulted her, including writing and drawing on intimate parts of her body and taking mobile phone photos of their actions.
The boys were arrested on charges of sexual battery and distribution of child pornography. Last month they were released from a juvenile detention centre and ordered into house arrest as they await trial.
In addition, Audrie's family claim a 15-year-old girl was present in the room when the assault occurred and encouraged the boys 'to expose and/or photograph and/or draw on Audrie's body', according to their lawsuit.
The new defendant, identified only as Jane C. because she is a minor, encouraged the assault and the taking of pictures. She then buttoned and zipped Audrie Pott's shorts, covered her with a blanket and left her alone, according to the lawsuit.
Days after the party, Audrie saw a group of students at Saratoga High School huddled around a mobile phone and realised that at least one humiliating photo of her was circulating.
Audrie tried to confront the boys accused of attacking her online, and posted her feelings about it on social media.
"I have a reputation for a night I don't even remember and the whole school knows," she wrote in one Facebook message to a friend.
"I cried when I found out what they did," she wrote in another.
Eight days after the party, Audrie Pott called and asked her mother to pick her up at school. She said she couldn't deal with it any more but would not say what was wrong. She later hanged herself in her home.
Audrie's father said: "She was picked on because she was pretty, because she was popular, because she was nice."