LOS ANGELES - A federal judge on Thursday provisionally threw out the convictions of a Missouri mother for her role in a MySpace hoax directed at a 13-year-old neighbour girl who ended up committing suicide.

U.S. District Judge George Wu said he was acquitting Lori Drew of misdemeanour counts of accessing computers without authorization but stressed the ruling was provisional until he issues it in writing.

Drew was convicted in November, but the judge said that if she is to be found guilty of illegally accessing computers, anyone who has ever violated the social networking site's terms of service would be guilty of a misdemeanour.

Drew's attorney Dean Steward said outside court that the U.S. attorney's office in Los Angeles should not have brought the charges in a case that originated in Missouri and was rejected by prosecutors there.

The U.S. attorney's office did not immediately comment on Wu's decision, which came after an hour of arguments.

The parents of Megan Meier, the teenager who killed herself, were in the courtroom but did not comment.

Prosecutors say Drew sought to humiliate Megan by helping create a fictitious teen boy on the social networking site and sending flirtatious messages to the girl in his name. The fake boy then dumped Megan in a message saying the world would be better without her.

She hanged herself a short time later in October 2006.

Drew was not directly charged with causing Megan's death. Instead, prosecutors indicted her under the federal Computer Fraud and Abuse Act, which in the past has been used in hacking and trademark theft cases.

Wu acknowledged in May he was concerned that sending Drew to prison for violating a Web site's service terms might set a dangerous precedent. Wu at the time noted that millions of people either don't read service terms, as happened in Drew's case.

During the trial, prosecutors argued that Drew violated MySpace service rules by setting up the phoney profile for a boy named "Josh Evans" with the help of her then-13-year-old daughter Sarah and business assistant Ashley Grills.

Prosecutors believe Drew and her daughter, who was friends with Megan, created the profile to find out if Megan was spreading rumours about Sarah. Grills testified she received a message from Megan in mid-2006, calling Drew's daughter a lesbian.

Grills, who testified under a promise of immunity, allegedly sent the final, insulting message to Megan before she killed herself. Prosecutors said Megan sent a response saying, "'You are the kind of boy a girl would kill herself over."'

Jurors decided Drew was not guilty of the more serious felonies of intentionally causing emotional harm while accessing computers without authorization. The jury could not reach a unanimous verdict on a felony conspiracy charge.