After hundreds of hours of investigation, Halifax Regional Fire and Emergency says it has been unable to determine the cause of the fire that killed seven children in their Spryfield home on Feb 19.

Chief Ken Stuebing said Wednesday that even though the fire department doesn't know the exact cause of the overnight fire, which started near a couch, investigators were able to determine it was not suspicious and there was no evidence any kind of accelerant was used.

The department also determined it wasn't a cooking fire or due to some kind of electrical fault or defect. The baseboard heaters were in the off position at the time and there was no other heating source in the home. There was also no evidence that the fire was caused by someone carelessly getting rid of cigarettes or other smoking materials.

"We investigated every piece of evidence available, and tested every possible theory to learn what we could about this fire. Despite our best efforts we are unable to say what caused this tragic event," said Stuebing.

The fire happened on Feb. 19, 2019. A memorial was set up in front of the home in memory of the seven children who died in the blaze. (Robert Short/CBC)

Smoke alarms were found throughout much of the house, but only the ones in the basement were intact enough to test. They all worked.

"We can say that the fire originated in the back of the house in the main floor living room, near a couch, however at this time the cause will be classified as undetermined," said Stuebing.

Since January 2015, the cause of 25 per cent of major fires in the Halifax Regional Municipality were classified as undetermined.

The fire department has now closed its investigation and has no plans to reopen it unless new information is discovered.

The Quartz Drive house fire led to the deaths of the Barho children: Abdullah, 3 months; Rana, 2; Hala, 3; Ola, 8; Mohamad, 9; Rola, 12; and Ahmed, 14.

Seven stuffed animals lined the porch of the Elmsdale, N.S., home where the Barho family first lived in Canada. (Angela MacIvor/CBC)

The children's mother, Kawthar Barho, managed to escape the blaze, but her husband, Ebraheim, was critically injured.

Fire officials would not talk about Ebraheim's current condition, but said they were not able to interview him during the course of their investigation.

It is not unusual for a fire of this magnitude to destroy evidence making it hard for fire investigators to piece together what happened, according to deputy chief David Meldrum.

"It's common for materials to be totally destroyed by fire or indeed removed or washed away by necessary firefighting activities, so this is also true here our fire investigators simply lack the physical evidence to make a conclusive determination of cause," said Meldrum.

Deputy Chief David Meldrum speaks at a news conference Wednesday outlining what Halifax Regional Fire and Emergency discovered during their investigation into a fire that killed seven children. (Shaina Luck/CBC)

The investigators say they could not find any evidence that the fire was related to the construction of the home or a manufacturing defect in the house. They do not believe there is an increased risk of fire to similarly built homes.

Not much information on the fire investigation was released until Wednesday.

The Barho family is originally from the war-torn Syrian city of Raqqa and lived briefly in Damascus before moving to Beirut.

The family arrived in Nova Scotia as refugees in September 2017.

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