A violent attacker may have stalked an isolated, well-known beauty spot in the Dublin mountains before targeting three innocent victims, the Herald has learned.
The shocking assault on the group of "completely innocent" young campers at the Hell Fire Club on Monday afternoon may have been "premeditated", gardai believe .
The attacker, who chose his victims at random, left two young men and a teenage woman requiring hospital treatment as a result of their injuries.
The incident happened in broad daylight when a group of people who were camping at the ruin were set upon by the man in his 20s.
One youth received a knife wound while his two friends received injuries consistent with an assault.
All three were brought to Tallaght Hospital for treatment but were discharged later that evening and have been recovering at home.
The family of the young man who received the knife injury have declined to comment but were left visibly shaken by the ordeal.
Gardai are satisfied that the attacker arrived at the Hell Fire Club alone, and was carrying the knife on him long before the attack took place.
"The three victims - whose injuries aren't too serious thankfully - were completely innocent in all of this.
"They were camping, minding their own business when they came across this individual," the source said.
"The fact that this man was walking around with a knife in his possession indicates that this may have been a premeditated, albeit random attack," the source added.
Gardai were last night continuing to interview a 26-year-old man in relation to the attack.
The suspect - who is originally from the Raheny area of the capital - has a number of previous convictions for public order related offences.
He was arrested on Monday evening in the Kilakee area of the Dublin Mountains - just a short distance away from where the attack took place.
It also emerged that a four-year-old boy - who was with his grandmother - witnessed two of the victims "covered in blood" in the immediate aftermath of the assault.
Local Fianna Fail councillor Charlie O'Connor described how the community was appalled by the attack and appealed for anyone with information to contact the gardai.
"I have been talking to people in the area and they are absolutely shocked at this incident.
"South Dublin County Council is trying to promote the Hell Fire Club so that people will go there, and a shocking incident like this certainly doesn't help," Mr O'Connor told the Herald.
"My thoughts are of course with these young victims and I wish them a speedy recovery.
"Anyone who was a witness or has information in relation to this attack should contact the gardai if they haven't done so already," he added.
Local councillor Francis Duffy, who lives close to the scene of the stabbing, said it was a very unusual incident to happen in the area.
The area is a popular spot for families and hikers but it wouldn't be the sort of area that would attract field drinkers or people taking drugs, he said.
"You get all sorts of walkers that go up there but it's a long way to walk," he told the Herald. The Hell Fire Club is situated on top of Montpelier Hill in the Dublin mountains.
It is known for offering impressive views of Dublin on a clear day.
The imposing stone building was built as a hunting lodge around 1725 by William Conolly, a speaker at the Irish House of Commons at the time.
Originally there was a cairn with a prehistoric passage grave at the site and folklore suggest that the Hell Fire Club is haunted because stones from the cairn were used in its construction.
It has also been suggested that the devil has appeared here and the place is associated with paranormal events.
Local superstition has it that if you walk around the building three times you see the devil.
Members of the Irish Hell Fire Club, which was active in the years 1735 to 1741, used Montpelier Lodge as a meeting place. Today it stands in ruins but can still be accessed via a concrete stairs.
The surrounding land is set in forestry controlled by Coillte, and the mountain is a very popular place for hill walkers.
However, it also has a reputation for attracting campers and youths, especially during the summer.
The shocking attack took place at around 3.45pm on Monday. Emergency services were alerted and gardai as well as paramedics rushed to the scene.