A 49-year-old US woman accused of pretending to be a love-struck teenage boy on MySpace and driving a 13-year-old girl to suicide with cruel messages has been indicted on federal charges.

US prosecutors say Lori Drew and others created the fake MySpace persona of a 16-year-old boy to woo neighbour Megan Meier for several weeks, and then abruptly ended the relationship and said the world would be better off without her.

Ms Meier's 2006 suicide by hanging, just hours after she read those final messages, made worldwide headlines and prompted calls for social networking sites like MySpace to crack down on cyber-bullying.

'This adult woman allegedly used the Internet to target a young teenage girl, with horrendous ramifications,' US Attorney Thomas O'Brien said in announcing the indictment in Los Angeles, where MySpace is based.

'Any adult who uses the Internet or a social gathering Web site to bully or harass another person, particularly a young teenage girl, needs to realise that their actions can have serious consequences,' Mr O'Brien said.

Experts said the indictment, which was handed down in Los Angeles after Missouri authorities declined to prosecute Ms Drew, was the first of its kind and could stretch the bounds of the federal statute on which it was based.

'We are in uncharted waters here,' University of Southern California law professor and former federal prosecutor Rebecca Lonergan said.

'This case is unprecedented and it's also a very aggressive charging decision.'

Ms Lonergan said Ms Drew was charged with accessing a protected computer to obtain information, a statute typically used against defendants who hack into government computers.

'While I think most people agree that it merits punishment to harass a young girl to the point where she commits suicide, it's not clear that this conduct is covered by this federal statute,' she said.

Fictional Boy

Prosecutors say Ms Drew, mother of a teenage girl who had a falling out with Ms Meier, and several others created a profile for the fictional 'Josh Evans' using the picture of an unwitting teenage boy.

They then contacted Ms Meier, who lived four doors away in O'Fallon, Missouri, through MySpace as 'Josh' and spent several weeks flirting with her before ending the relationship on 15 October 2006.

Several hours after the final message, Ms Meier, who had argued with her mother over the relationship, hanged herself in the closet of her bedroom in a St Louis suburb, still unaware that 'Josh' did not exist.

The indictment charges that after Ms Meier killed herself, Ms Drew had the phony MySpace account deleted and warned a girl who knew about it that she should 'keep her mouth shut'.

After the incident became widely known, the Drew family was shunned by members of the community, targeted for abuse on the Internet and their small advertising business was vandalised.

Ms Drew, who faces a maximum sentence of 20 years in federal prison if she is convicted on all of the charges, was expected to surrender to authorities in Missouri.

A foundation focused on tackling cyberbullying has been set up in Megan's name. Click here for the website.

Prime Time Investigates cyberbullying Monday at 9.30p on RTÉ.ie/livePrime Time Investigates looks at cyberbullying in Ireland. Watch it on Monday 19 May at 9.30pm on RTÉ.ie/live and RTÉ One Television.