The fire that claimed the lives of the seven members of the McElhill family in Omagh, Co Tyrone, was caused by a "significant quantity" of petrol poured and then ignited at the scene, the PSNI has confirmed.
The PSNI has now launched a murder inquiry. Police believe that the McElhill family home erupted in flames before 5am on Tuesday as a result of arson. They are trying to determine if the accelerant was lit from inside the building.
By 5pm last night all seven bodies were located inside the blackened, gutted house at Lammy Crescent in Omagh. It is hoped that the bodies of Arthur McElhill, his partner Lorraine McGovern, and the five children - Caroline (13), Seán (7), Bellina (4), Clodagh (18 months) and James (nine months) - will be removed from the house today, or at the latest tomorrow.
The fire, the PSNI confirmed yesterday, was triggered by petrol sprayed and then lit at the scene. At about 11am yesterday Det Chief Supt Norman Baxter told reporters that the area was a potential crime scene. Three hours later he said 30 detectives and support staff were drafted in to carry out a major murder inquiry.
"We have now moved to the position where we are saying this is a crime scene and we have commenced a murder investigation," said Det Chief Supt Baxter.
"I have to say that this is one of the most tragic and devastating murder inquiries the PSNI has had to encounter with the loss of so many young lives."
A key question is whether the petrol was poured from outside the house or from inside. This would indicate if a killer or killers of five children and their parents remain at large.
On Tuesday Det Chief Supt Baxter would not comment directly on local rumours that there was some form of "commotion" at the McElhill house at about 3am that morning, less than two hours before the fire, involving Mr McElhill and Ms McGovern.
Yesterday he was asked if police were looking for anybody in the community in relation to the fire. "It is too early at this stage to rule anything in or anything out," he said.
Asked was there any suggestion Mr McElhill might be a suspect, he replied: "As I said earlier it is too early to comment on exactly what's happened in this home. There are a number of possibilities. There are a number of lines of inquiry."
Lammy Crescent yesterday was still a scene of great shock, grief and loss. Throughout the day friends of the McElhills, neighbours, and boys and girls who went to school with the children, arrived to lay flowers and notes of condolence.
Further details also emerged yesterday of how some local men frantically and courageously tried to rescue the family. Brothers Mark and John McGlynn rushed with ladders to the scene.
They discovered Arthur McElhill at an upstairs window but he was "too far through" from smoke inhalation to make an effort to be saved. Mark McGlynn told the BBC that Mr McElhill just stared shocked and helpless out of the window for a "long three, four seconds" and was then overcome.