OTTAWA — The suicide of a Canadian girl tormented by an anonymous cyberbully has sparked a national debate in Canada on what is appropriate online behavior, calls for criminalizing the cruel practice and a police warning on Tuesday against vigilantism.

In a YouTube video watched by millions worldwide, Amanda Todd, 15, said she suffered from anxiety, "major depression" and panic attacks after a photo of her breasts, flashed in an online video chat with a stranger in Grade 7, was distributed in her community in Canada's westernmost British Columbia province.

She said she withdrew and turned to drugs and alcohol, and "cried every night."

In the video Todd laments a lack of friends due to the controversy, a schoolyard beating over a boy and changing schools several times to escape blackmail. She says, "I have nobody. I need someone."

After several failed suicide attempts and posting the YouTube video describing her sadness, Todd finally killed herself on October 10.

Her death has led to discussions at schools, in the media, in political circles and at kitchen tables nationwide about how to keep youths with a lot of technical knowledge but no life experience -- a combination that makes it hard for them to assess risk and imagine future consequences -- safe online.

British Columbia Premier Christy Clark went so far as to call for criminalizing cyberbullying.

Then on Monday, the hacker group Anonymous identified a 32-year-old man in the Vancouver area as Todd's anonymous tormenter, saying he frequented websites aimed at teenage girls.

The man allegedly tried to blackmail Todd, according to her YouTube posting, saying after her indiscretion that he would widely distribute the photo of her breasts if she didn't "put on a show" for him. She refused.

Todd's mother told Canadian media she believes her daughter's tormentor actually resides in the United States but authorities have not identified him.

Anonymous's outing of a Canadian suspect, who has denied involvement in the case to local media, prompted federal police to issue a warning against vigilantism, saying vigilantes "run the risk of committing a criminal offense." Anonymous is believed to be a loosely affiliated network of "hacktivists."

Meanwhile, a memorial Facebook page set up for Todd, who longed for a circle of friends when she was alive, has amassed nearly one million "likes."