The partner of a man who was fatally stabbed at her home on Wednesday night arrived at the scene shortly after the attack, it has emerged,
A man subsequently handed himself into gardaí and was being questioned yesterday.
DNA and forensic samples were taken and efforts were being made to locate the blade used in the killing.
Bryan Cassidy, aged 52, died after suffering a number of stab wounds while inside his partner’s house on Buirg an Rí Walk, in Balgaddy, west Dublin.
Mr Cassidy, from Heuston Square, Inchicore, in the south inner city, managed to leave the house.
He went two doors down the cul-de-sac in an apparent bid to seek help before collapsing in the front garden of a neighbour’s house.
Emergency services were alerted at 10.25pm. The Dublin Fire Brigade discovered his body and saw that he had suffered stab wounds. He was pronounced dead at the scene.
Local sources said the man’s partner arrived home soon after and emergency services tried to comfort her.
Gardaí sealed off two scenes, where the stabbing occurred and where Mr Cassidy collapsed, pending a full technical examination.
A tarpaulin was placed around the deceased.
The Garda Technical Bureau began their work yesterday morning and a state pathologist arrived, before the body was removed for a full postmortem.
The road is adjacent to a national school and children were passing by the area yesterday.
In a statement, gardaí said that a 19-year-old man was arrested shortly after midnight.
It is understood he voluntarily turned up at Ronanstown Garda Station.
He was detained under Section 4 of the Criminal Justice Act 1984, which allows for a total detention period of 24 hours, excluding rest breaks.
It is understood that the 19-year-old does not have a criminal record and has not had any significant interactions with gardaí before.
He is thought to have known the deceased, but is not related to him.
Senior officers were in contact with the Director of Prosecutions last night as to whether or not charges should be brought today.
Sources said gardaí were following a definite line of inquiry and were not looking for anyone else in relation to the death.
They have asked people who were in the area at the time and who may have seen or heard anything to contact gardaí.
They can call Lucan Garda Station on 01-666 7382, the Garda Confidential Telephone Line on 1800 666 111, or any other garda station.