Gardai are investigating whether a sex attacker lured two little girls - aged six and nine - to his apartment after telling them there was a little girl there who was "lonely" and wanted to play with them.
More details are beginning to emerge this morning about the "horrific, catastrophic ordeal" suffered by the two little girls in Athlone on Saturday afternnoon.
It has also emerged that a man being questioned about the serious sex assault had only recently been released from prison. However, he is not on the sex offenders' register.
Three men were arrested - but two were released from custody this morning and a file has been prepared for the Director of Prosecutions.
A third man - who is known to gardai - remains in custody.
The Minister for Justice Alan Shatter this morning confirmed that none of the men held in relation to the incident were previously committed for sexual offences.
"I understand the concerns of the wider community, and I feel it is important I set the record right on that issue", he told Pat Kenny on Newstalk.
Meanwhile, investigating gardai have engaged the services of trained specialist interview to ascertain what exactly happened to the two little girls on Saturday afternoon.
The girls were subjected to what gardai called "a horrific, catastrophic ordeal" after being lured from a children's birthday party in Athlone, Co Westmeath.
They were playing outside and are understood to have been tricked into going to a nearby house where they were both severely sexually assaulted.
It's understood that the two little girls were approached by the man on Saturday afternoon who told them there was a third little girl in his apartment and she was on her own. It's believed he told the victims this little girl wanted to play with them, and the victims followed him to his apartment building.
Once there, the little girls were assaulted.
They managed to escape through a rear exit of the building and made their way back to the house where they managed to tell adults what had happened to them.
In the meantime, the alarm had been raised by adults at the house who had noticed the two little girls were missing.
The traumatised children were rushed to hospital in Galway for emergency medical treatment after fleeing from the house by climbing through a window.
A garda source told the Irish Independent: "This is an extremely serious case and it is not an exaggeration to say that what happened to these innocent children is absolutely catastrophic. They endured an experience that is the stuff of every parent's nightmare.
"The girls are deeply traumatised, and it will take a long time for them to recover from this horrific ordeal."
The area of Athlone where the incident is alleged to have taken place has been described locally as "well-to-do" and "well-established". The houses were built more than 40 years ago and there are many young families in the estate.
Neither of the children is local. They travelled from other parts of the country for the party and had been staying with relatives.
They are believed to have been enticed to the nearby house by a man who was not attending the celebration.
Once inside, they were taken to a room where each was severely sexually assaulted.
Both of the girls were highly distressed, but managed to escape when they climbed out a window and ran back to the house where the party was taking place to raise the alarm.
The adults at the party were horrified by what the traumatised children told them.
The girls identified the house where the attack had taken place, and a number of men went there to confront the alleged attacker.
It is understood that a fight broke out as gardai arrived, and the three occupants of the house were arrested for public-order offences.
Gardai are now understood to be concentrating their investigation on one of the three men who is known to them and was recently released from prison.
A source added: "The prompt arrival of the gardai may have saved the accused man from being seriously assaulted, because understandably, people were horrified at what had happened and tempers were running high."
The three men were taken to Athlone garda station where they were questioned. Two of them were released this morning without charge.
Meanwhile, the two girls were rushed to University College Hospital in Galway, where they both underwent extensive examination and were detained for medical treatment.
Their parents were also at the hospital yesterday after being alerted to the incident.
A garda source added: "There is enormous upset at what has happened. The children will be given every specialist care that is required, but this will stay with them for the rest of their lives."
Labour Party councillor Jim Henson said people in the tight-knit Athlone community had been left stunned by news of the alleged attacks.
He said: "It frightens people to think that this sort of thing could happen in their community.
"My thoughts and prayers are with the parents of the two young girls."
The town's mayor, councillor Gabrielle McFadden, also reacted to news of the incident saying: "It's horrific and as a parent you wouldn't want that to happen to anybody."
She added: "I'm the mayor of the town. I don't want it going in a national newspaper that this is how awful Athlone is. It's not.
"It's very nerve-racking to let your children out, but it could happen anywhere to anyone."
By Paul Williams and Cormac McQuinn