A fourth person, believed to be an infant child, was killed in Tuesday's fire at a house in Derrylin, Co Fermanagh, police have said.
Detectives from the PSNI’s serious crime branch investigating the circumstances surrounding the fire in a house on Molly Road said a fourth body had been found.
“It is with great sadness that I can now confirm that a fourth body has been found within the crime scene and that it appears to be the body of a young child,” said Det Insp Peter McKenna.
“Postmortem examinations will take place in order to positively identify the victims involved in this appalling incident.
“I believe the fire was started deliberately and we are working hard to progress the investigation into this very complex crime scene. There is significant structural damage caused by the ferocious fire and the scene examination is further compounded by the severe weather.”
Det Insp McKenna said the 27-year old man arrested by police at the scene on suspicion of murder, who had been under police guard in hospital, had been moved to police custody for questioning.
Those killed in the blaze were a mother and her two children originally from Doncaster in England, who had previously lived in Tralee, Co Kerry, before moving to Fermanagh about 12 months ago.
They have been named locally as Crystal Gossett, her son Edward (16) and daughter Diane (19). The fourth victim is believed to be Diane's infant daughter.
Landlord Tommy Fee who tried in vain to rescue the family from the burning house by smashing the door with a sledgehammer, recalled seeing the baby in the house when he was asked to fix a fuse in the bathroom about a month ago.
“The wee child was playing up and down on the kitchen floor; she would try to get up and run from here to the kitchen door and would fall and had the hands out to balance herself.
"That image is in my head, that wee child, you wouldn't forget that in a hurry," he told The Impartial Reporter newspaper.
Four white tents for each of the bodies have been erected by police on a farm next door as specialised officers work in plummeting temperatures near Doon Mountain in a bid to determine how the deaths occurred.
Det Insp McKenna said: "I would like to thank the public for their assistance so far and would appeal for anyone who knew of or has any knowledge of the residents of 57 Molly Road Doon, Derrylin, to make contact with police. I would also like to hear from anyone who was in the area of Molly Road between the hours of midnight on Monday through to 7.20am on Tuesday morning."