AMERICAN authorities investigating the suicide of a 15-year-old Irish schoolgirl last month have obtained a grand jury subpoena allowing them to examine certain discussion groups on the popular social networking site Facebook, the Sunday Tribune has learned.

Phoebe Prince, a first-year student at South Hadley High School in Massachusetts, took her own life last month after a sustained campaign of verbal abuse and "cyber-bullying" by fellow students.

They reportedly taunted the teen through text messages and on Facebook; those involved allegedly posted disparaging messages on a Facebook memorial page set up after her death.

Originally from Fanore in Co Clare, Prince had moved to South Hadley with her family only last September.

It is understood that the records sought by police include one Facebook discussion group entitled 'We murdered Phoebe Prince'. It is believed that two other Facebook discussion groups will also be examined to establish the nature of the comments posted online.

A grand jury subpoena, dated 9 February, also allows for records relating to Craigslist and Microsoft to be examined.

A spokeswoman for Northwestern district attorney's office told the Sunday Tribune it was "too early to say" if there would be criminal prosecutions arising out of Prince's death. However, she confirmed that students at the school have been interviewed by police in recent weeks.

"All I can say right now is that the investigation is active and ongoing," she added.

The school's superintendent, Gus Sayer, said authorities there first learned that Prince was a victim of bullying one week before her death, when a student at the high school entered her classroom and yelled at her using a vulgar name.

"That student was disciplined immediately and suspended," Sayer told the Sunday Tribune. "The principal did not learn of any other acts of bullying by other students until an investigation took place after Phoebe's death. Immediately following that event, students posted messages on Facebook that indicated other bullying acts by other students had taken place."

The school's principal, Dan Smith, followed this up and interviewed 20 to 30 students to confirm the incidents had occurred.

"These involved a small group of students, with almost all of the incidents occurring during the last week of Phoebe's life. The students have been suspended from the high school pending the scheduling of hearings to consider whether they should receive long-term suspensions, expulsions and possible referral to the police for criminal investigation. Because of the involvement of attorneys at this point, this process takes two to three weeks and should be completed in another week or so."

A spokeswoman for Facebook said she could not discuss details of any ongoing investigations by law enforcement "other than to confirm we take such matters seriously... We have a team dedicated to supporting law enforcement and are proud of our excellent record assisting with a broad range of cases related to child safety. We have very strict policies around inappropriate content, and are quite vigilant, proactively policing and ensuring a 24-hour response time globally related to abuse/bullying reports."