A second daughter, aged six, was rescued by firemen and is in a critical condition in hospital with burns.
PC Philip Hobby, 25, made three attempts to enter the semi- detached home on the Sandfields housing estate at Port Talbot, West Glamorgan, but was beaten back by heat and smoke. 'I was halfway up the stairs when I felt a sudden gust of warm air, a flash, went over my head,' he said. 'It was incredible. A fire-ball went right through the house.'
The dead were Violet Williams, 40, a mother of five, her boyfriend, Dennis Elliott, 41, Mrs Williams's daughter Nicola, nine, Gareth Morris, 37, who was staying overnight at the house along with Thomas Bartle, 68, of Gloucester House, Sandfields. Carly Williams, six, is in intensive care.
Detective Chief Superintendent Phil Jones, head of South Wales CID, said the blaze started in the downstairs living-room and spread quickly to the upstairs bedrooms, where most of the victims were trapped.
Neighbours saw Mrs Williams at a bedroom window but were unable to help her because of the intensity of the fire. The gutted house is only 50 yards from the estate's police station.
Mrs Williams's ex-husband Aubrey, 40, who lives across the road, was among the would-be rescuers but he could not get into the burning house. He was said to be too upset to talk.
A neighbour said that she heard shouts outside at about 11pm. 'It happened so quickly and there was just nothing anybody could do to get to them.'
Jim Windsor, West Glamorgan's chief fire officer, said: 'The house is gutted from top to bottom and the fire spread very quickly. 'A good smoke detector costs only a fiver,' he added. 'Tragically, that's a pound a life in this case.'
Later Port Talbot borough council accepted criticism that smoke alarms were not fitted at the council house.
Police do not suspect crime.