An 18-year-old son of Sinn Féin TD Aengus Ó Snodaigh is in a serious condition in hospital after a stabbing overnight in the Bluebell area of Dublin.
He was treated by emergency personnel after the incident at a house on the Old Naas Road at about 12.30am.
He was then taken by ambulance to St James's Hospital.
The scene has been preserved for a technical examination.
Anyone with information on the incident is asked to contact Kilmainham Garda Station on 01-6669700 or the Garda Confidential Line 1800 666 111.