The PSNI and Northern Ireland Fire Service have launched investigations to establish if there was anything "untoward" behind the fire that it is feared killed all seven members of the McElhill family in Omagh, Co Tyrone.
Arthur McElhill, his partner Lorraine McGovern and their five children aged from 10 months to 13 years are believed to have died in the blaze that engulfed their end-of-terrace home at Lammy Crescent, Omagh yesterday morning.
The operation to recover the seven bodies was scaled down last night. Fire officers hope to remove them today.
So far the remains of five bodies have been located, although the police and fire service believe all seven members of the family died.
Local Independent councillor Paddy McGowan, a former fire officer who arrived early at the scene, said locals spoke of despairingly trying to rescue the family. One local also said he saw the children's parents attempting to escape from a first-floor window before being overcome by the smoke and flames.
Fire crews were alerted shortly before 5am but when they got to the scene they found the house in flames. The North's deputy fire officer Louis Jones said it was one of the worst fire tragedies he had encountered in 30 years' service.
"Despite the intensity of the fire our firefighters entered the building using fire apparatus and tried to effect rescues. However, due to the intensity of the fire we were unable to do so," he said.
Det Chief Supt Norman Baxter said the PSNI was carrying out a full and thorough investigation to "try to establish if there were any untoward circumstances". "We are considering all possibilities but there is nothing at this stage to indicate there was a definite crime," he said.
The victims of the fire, one of the worst such tragedies in Northern Ireland, were named locally as Arthur McElhill, believed to be from a farming background and originally from near Ederny, Co Fermanagh, and his partner, Lorraine, believed to be originally from Co Cavan.
They moved to Omagh in the past four years. The children who died were Caroline (13), who was a student in the secondary Sacred Heart School in Omagh; Sean (7) and Bellina (4), both pupils in St Conor's Primary School, just yards from the family home; and Clodagh, aged 18 months, and James, aged 10 months.
The building was a Housing Executive property. Mr Jones said these buildings usually had smoke detectors fitted but he could not say whether they were fitted in the McElhill home. One fire officer said it seemed likely the fire started on the first floor.
Initially yesterday fire crews sifted through the blackened shell of the house. However, because the roof had caved in, it was later deemed too dangerous to continue this work. Police, firefighters and forensic officers also examined the scene from a hoist placed close to the building.
First Minister the Rev Ian Paisley and Deputy First Minister Martin McGuinness expressed their horror. Taoiseach Bertie Ahern said "the loss of so many lives from one family is truly heartbreaking".