Three children's bodies have been removed from a house in Co Dublin.
Gardaí said that the deaths are "unexplained".
It is believed the family moved to Newcastle about a year ago.
The discovery was made at Parson's Court in Newcastle at around 7.00pm on Friday.
Irish police say they found no evidence of anyone in the house at the time the children died, and there were no signs of a break-in at the property. After he discovered a note there saying "Call 999, don't go upstairs", he alerted authorities.
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Three children found dead in a house in Co Dublin after an "unexplained" incident have been named as brothers and sister Conor, Darragh and Carla McGinley.
According to The Sun, Gardai suspect the three children may have been "drugged" or "poisoned". She was taken to Tallaght Hospital and there are hopes she can speak to detectives soon.
Garda forensic collision investigators have examined the crash site and both vehicles involved.
Gardaí say the results of the post mortem will determine the cause of death of the children.
Assistant State Pathologist Margot Bolster has attended the scene.
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Gardai said a family liaison officer was in contact with their father Andrew McGinley and the extended family.
"My thoughts are with everybody impacted", the Fine Gael representative said.
"This is a really tight-knit community, it's a small area, it's a quiet area, and it's just unthinkable that something like this could be happening on our doorstep".
Anyone with information is asked to contact Clondalkin Station 01 6667600 or the Garda Confidential Line 1800 666 111.
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