A federal grand jury has subpoenaed MySpace in an investigation into the suicide of teenager Megan Meier.

The girl killed herself after being harassed by someone on MySpace, whom she believed to be a boy but who was in fact the parent of a schoolmate.

Dardenne Prairie, the town where Meier lived, has since passed laws against such activity, but the federal authorities had said that there was nothing they could do.

The case has sparked a national furore, however. The family behind the harassment has been forced to move, and legislators are considering a national online bullying law.

Police in California are now investigating to see whether they can prosecute the parent for defrauding the MySpace social networking website after she set up a false identity on the site.

Los Angeles police feel that they have jurisdiction since MySpace is headquartered in Beverley Hills.

"If MySpace is considered the victim, fine. I do not care at this point," Tina Meier, Megan's mother, told the Los Angeles Times.

"We have been begging for someone - anyone - to pick up this case. If the Drews can be charged, and even get the chance to be convicted, it would be a day I could be happy with."

Thomas P. O'Brien, US attorney in Los Angeles, declined to comment, but the Los Angeles Times cited an anonymous source who claimed that several subpoenas have been issued, including one to MySpace.

Former federal prosecutor Brian C. Lysaght said that such a prosecution would be "not as much of a reach as it might appear at first glance".

Kurt Opsahl, a senior staff attorney at the Electronic Frontier Foundation who specialises in privacy and free speech issues, suggested that the potential of this case to set legal precedent criminalising online speech is worrying.

"The right to speak freely online is hugely important. Whistle-blowers create pseudonyms," he said.

"So do many people who anonymously report on corporate or government bad practices."