Tyler Long was a happy little boy. But at 17, he committed suicide because he was bullied at school, says his father David Long. "We had heard that he had his head shoved into a wall locker. So kids had told him to go hang himself. That he is worthless. And I think he got to the point where enough was enough," he said. 

Tyler's story is one of five family accounts director Lee Hirsch presents in Bully, a harrowing documentary about bullying in schools.

"It happens in urban schools, it happens in rural schools. I don't believe that the problems the families in this film experience are unique to small town America," he said. 

From the Long family in Georgia, the film takes us to Alex Libby and his family in Iowa. For years, Alex endured abuse at the hands of his schoolmates. "They'd punch me, strangle me, sit on me," he said. 

The film follows Alex's mom as she confronts the school principal who seems to be in denial. 

But Lee Hirsch managed to capture the abuse on camera. "We weren't a big production, there's no lights, there was no sound person, there was just me with a tiny Canon, what looked like a consumer camera. So, I think that they acted as they normally did, and that was, to feel that it was okay to pick on Alex," he said. 

Bully is an emotional rollercoaster that takes us next to Oklahoma and to Kelby, a lesbian. "When I opened my locker there was a note that said '[gay people] are not welcomed here.' Then the teacher was calling roll and said boys, and then he said girls, and then paused and said Kelby," she said. 

The film's power lies in the heartbreaking testimony of these socially isolated kids and their parents. Some of them have lost their kids forever. The movie aims at educating and mobilizing people against bullying. 

The Motion Picture Association refused to give Bully a PG 13 rating so teens could watch it. The reason was explicit language used by bullies against their victims and captured on film. 

About half a million people opposed the ruling by signing an online petition drafted by Katy Butler. Butler, a bullied teen from Michigan, wrote the petition after watching the film. "I want to make sure that every school in the United States and hopefully beyond that knows how important this movie is and ends up showing it in schools so the kids can actually see it," she said. 

Her efforts paid off. At the last minute, the MPAA granted the film a PG 13 rating. Bully is expected to be a box office hit when it opens nationwide on April 13.