Two young children were among four people hospitalised after a house fire in west Dublin.
Emergency services were alerted to the blaze on Aylmer Drive in Newcastle at around 5am yesterday.
Four people were in the house at the time including two young children.
Three of them were rescued by members of the Dublin Fire Brigade using a ladder.
The fire was extinguished by crews using breathing apparatus.
Irish Independent Senior Journalist Robin Schiller told Newstalk Breakfast a criminal investigation is underway.
"Thankfully they were safely removed and taken to hospital for non life-threatening injuries," he said.
"It became fairly clear fairly soon that it wasn't an accident, the fire was malicious.
"GardaĆ in Clondalkin are now carrying out a criminal investigation.
"They believe a front window was smashed and a firebomb thrown into the house causing the fire.
"GardaĆ are following a number of lines of inquiry, and certainly early indications are that this fire may have been caused by somebody known to the homeowners.
"There's been previous incidents at the house and it may be linked to not a criminal dispute in the traditional sense, but certainly a personal dispute that has now escalated," he added.
Anyone with information is being asked to contact Clondalkin garda station.