We're going to turn to new details in the case of two florida girls, accused of bullying a classmate so viciously, that police say she committed suicide. The bully at the center of the case is coming... See More
We're going to turn to new details in the case of two florida girls, accused of bullying a classmate so viciously, that police say she committed suicide. The bully at the center of the case is coming forward, heading light on what happened. And abc's matt gutman has the story. Reporter: Police say the relentless bullying that may have caused 12-year-old rebecca sedwick to kill herself, erupted out of jealousy over the attention of a boy, john borgen. How often do you think about rebecca? I think about her almost every day, knowing she had gotten bullied. I could have topped it. Reporter: Borgen is currently dating the 14-year-old, who police say is one of the girls who told rebecca sedwick she should drink bleach and die. And she should kill herself because she is ugly. Last month, sedwick did kill herself. That 14-year-old is now in jail. She and another 12-year-old were charged with felony aggravated stalking. The 12-year-old is under house arrest. But the worst of the alleged bullying came after sedwick's death. The 14-year-old put out a post. Yes, I bullied rebecca. Now, she's dead. And I don't care. Do you know about that? Yeah. I thought somebody hacked her account. Reporter: Now, borgen says he's on a mission to expose bullies. Speak up if you see somebody that is being bullied. Yeah. Don't be afraid. Reporter: If borgen's on a mission -- polk county sheriff grady judd is on a crusade. They can never get away. When they leave school, and they go home, the bullying continues. Sometimes 24/7. Reporter: At a town hall meeting overnight, the sheriff revealing clear warning signs that rebecca may have wanted to end her life. We saw on her facebook -- how many over-the-counter drugs do you take to die? We must listen to our children. We must give them the opportunity to open up. Reporter: And this morning, the internet, once the source of her torment, now, the site of an online petition for a new law, giving schools more power to stop cyber bullying, to be named after becca. To give you a sense of how long this online bullying might have gone on, borgen said he and sedwick had been exchanging videos online since the third grade. One of the last tragic acts of sedwick's life was to change that facebook profile to that dead girl. George? Matt gutman. Such a sad story.
This transcript has been automatically generated and may not be 100% accurate.