Until his late teens, Lee's street fights became more frequent and included beating the son of a feared triad family. In 1958, after students from Choy Li Fut, a rival martial arts school, challenged Lee's Wing Chun school, he engaged in a fight on a rooftop. In response to an unfair punch by another boy, Bruce beat him so badly that he knocked out one of his teeth, leading to a complaint by the boy's parents to the police. Lee's mother had to go to a police station and sign a document saying that she would take full responsibility for Bruce's actions if they released him into her custody. Though she did not mention the incident to her husband, she suggested that Bruce, being an American citizen, return to the United States. Lee's father agreed, as Lee's college prospects were he to remain in Hong Kong were not very promising.