GARDAI investigating the death of Erin Gallagher have formally questioned three teenagers about bullying allegations.
The revelation comes as the boss of social networking ask.fm rejected claims that her death was linked to website bullying.
Gardai carried out more interviews with three school girls and their families yesterday.
They met two of the teenagers earlier this week, who voluntarily attended a garda station along with their parents.
The development came a day after the 13-year-old was laid to rest after funeral Mass in Stranorlar and just hours after the founder of Ask.fm rejected links between his site and the deaths of two Irish teenagers.
Erin took her own life last weekend at her home in Co Donegal. Fifteen-year-old Ciara Pugsley died by suicide near her home in Co Leitrim in September.
Both Erin and Ciara had been taunted by vile messages by anonymous posters on ask.fm.
But the website's founder Mark Terebin insisted the media was "knocking on the wrong door".
"It is necessary to go deeper and to find a root of a problem. Its not about the site, the problem is about education, about moral values that were devaluated lately," said Mr Terebin on his own site.
He said his site, based in Latvia, was "just a tool which helps people to communicate with each other, same as any other social network, same as phone, same as piece of paper and pen".
He told Dublin-based documentary-maker Lynne Nolan: "Don't blame a tool, but try to make changes ... start with yourself... be more polite, more kind, more tolerant of others ... cultivate these values in families, in schools." He also blamed TV and newspapers for its coverage of suicides for further deaths, rather than ask.fm.
He said: "Suicide is not something to encourage via mass media. The more you promote suicide, the more it happen. Do you think mass media cares?
"They want scandals, they want sensations and finally they want money.
Meanwhile, gardai questioned the children about comments left on websites as well as texts sent to Erin's phone.
"This is a hugely sensitive investigation because it involves children," said one source.
"There is a great deal of tension in Stranolar and Ballybofey after Erin's death and gardai are keen to calm the situation.