The fire killed a couple and their five children aged nine months to 13 years in their home in Omagh, Northern Ireland, on Nov. 13.
Community sorrow turned to shock when it was revealed that the father, Arthur McElhill, was a twice-convicted sex offender who was suspected of dousing the home in gasoline before setting it alight.
A police statement said detectives were no longer looking for a suspect the force's first official admission that a family member, not someone outside the house, torched the two-story home.
The statement added that someone set a fire at the bottom of the ground-floor stairs, trapping those above. It said the eldest child, Caroline McElhill, died with a telephone receiver in one hand after making an emergency call and Roman Catholic prayer beads in the other.
Northern Ireland's police department has declined to clarify whether the statement meant detectives had positively identified Arthur McElhill as the arsonist, or whether any other family member might be responsible.
The statement followed Saturday's joint funeral service for McElhill, 39, and his common-law wife Lorraine McGovern, 30; daughters Caroline, 13, Bellina, 4, and Clodagh, 18 months old; and sons Sean, 7, and James, 9 months old.
The McElhill and McGovern families agreed to a joint Requiem Mass, but afterward McElhill was buried in a different cemetery.
Following the fire, detectives told The Associated Press that McElhill was their only suspect. But the police department declined to confirm it officially, describing all seven as murder victims.
The policeman who led the investigation, Detective Chief Superintendent Norman Baxter, said he intended to nominate Caroline for a posthumous award of courage because she tried to save the family from the fire.
Baxter said the girl called Northern Ireland's emergency services number at 4:54 a.m. on Nov. 13, just minutes before the blaze destroyed the home. He declined to specify what police heard Caroline say during the call.
He said Caroline "had the presence of mind and bravery to seek help from the emergency services to save her family."
"Caroline was recovered with her telephone in one hand and her Rosary beads in her other hand," he said. "This was a young girl, an emblem of innocence, with the courage to seek help and turning to her faith in the midst of fear and danger."
Arthur McElhill was on the Northern Ireland list of registered sex offenders after being convicted of sexually assaulting two teenage girls in the mid-1990s.