A faulty heater is likely to have started the fire which claimed the life of a man in Dublin, investigators believe.
They are satisfied that the blaze was accidental and are examining if a heater that had been in use on one of the first cold mornings of autumn could have triggered the blaze.
It is understood the fire started in the downstairs part of the property before spreading at the rear of the period redbrick house on Grove Park on the banks of the Grand Canal in Rathmines.
The fire broke out at around 7am yesterday while many of the residents were still asleep.
The building is split into a number of flats, and investigators are trying to establish if the victim, who was named locally as Jason Coll, who was in his 40s, was in the flat where the fire occurred, or if he succumbed to the smoke while in a neighbouring flat in the building.
A neighbour described the distressing scenes as emergency crews battled to save the victim's life.
"I looked out the window and saw people running around, semi-dressed in dressing gowns and nightclothes and things," he told the Herald.
"I could see black smoke billowing out the back of the building.
"At that point, the fire services had not arrived, but then I heard the sirens.
"Within minutes, they were here and the ambulance was here too."
The witness added: "About 20 minutes later, I saw this guy being hauled out into the hallway and the fire people doing CPR on him.
"It was very intensive, and they kept it up for 10 minutes maybe, and then they put him on a stretcher, still carrying out the CPR, and put him in the back of an ambulance and drove away with him.
"He looked to be a youngish male.
"Two people were taken out the top window on the left with ladders before the emergency services arrived - by locals, I believe."
Dublin Fire Brigade confirmed eight of its units, including three ambulances and a district officer, attended the blaze.
Gardai were also immediately on the scene to oversee and assist in the rescue and evacuation operation.
"Crews using breathing apparatus entered the building and four people in total were removed," confirmed a spokesman for Dublin Fire Brigade.
"Sadly, one of the casualties died, and another suffered extensive burn injuries to their hands and arms.
"The other two were less seriously hurt."
The injured were taken to St James's Hospital from the scene, where the victim was subsequently pronounced dead.
"There is nothing to suggest a sinister motive behind this, and at the moment it appears that a faulty heater led to the fire," a source said. Independent Councillor Ruairi McGinley said he believed a report on fire safety had been done on that stretch of road in the last three years by the council.
"It's all multi-tenant housing there in those houses," he said.
"They're old-style housing accommodation.
"Having said that, it is a very sad time for the man's family, and you would think of them at this stage."
Labour Councillor Mary Freehill said the incident was "very worrying" for the people living in the accommodation.
Ms Freehill said there were a number of people living in flats in the Georgian houses and that the tragedy was a reminder to everyone how paramount fire safety is.
"I became aware of it this morning before I boarded a plane and became immediately worried for the safety of the houses and flats there," she said.