OTTAWA -- A dry Christmas tree that caught fire was responsible for a deadly blaze south of Ottawa that left four people dead earlier this month, investigators have found.

The fire at a log home on Stone Road in North Grenville broke out on Sunday, Jan. 10 before 6 p.m. and quickly destroyed the home.

Investigators have found the fire started when a dry Christmas tree ignited, fully engulfing the building in flames.

“The homeowners had two friends over for dinner when the Christmas tree caught fire and the flames rapidly spread through the home,” said Kristy Denette, spokesperson for the Office of the Fire Marshal. “This happened so quickly that all four people in the home were unable to escape.”

Investigators were unable to determine what ignited the tree because the home was so badly damaged, she said. However, most cases fires involving Christmas trees are caused by electrical wiring failures with the Christmas lights.

“This demonstrates just how dangerous a dry Christmas tree is,” Denette said, adding that one of the investigators likened it to pouring five litres of gasoline in your house.

“These string lights, they’re very thin wires, so it’s really important that people check their Christmas tree lights for any damage or recalls,” Denette said.

The home had a smoke alarm, but investigators were unable to determine if it was operational due to the extensive damage.

Officials have not released the victims’ names, but Holy Cross Catholic Church in Kemptville has identified them as John and Carol Rouillard and Bob and Gina Juneau.

The church held an online memorial service for the two couples on Saturday. In a Facebook post, the church said they were longtime friends and members of the Holy Cross parish and the North Grenville community.

Neighbours told CTV News Ottawa at the scene that the homeowners were kind and caring people who had built the three-storey log home in the 1980s and had lived there ever since.

The deadly fire was the second in Ontario this holiday season to be caused by a Christmas tree catching fire.

On Dec. 28 in Halton Hills, Ont., a couple had just woken up when their tree caught fire. The man tried to use a fire extinguisher to douse the flames, but they spread too fast. He was rescued from a second-floor balcony by firefighters, but his wife was unable to escape and died.

The homeowners had planned to dispose of their tree that day.

“We would urge people to get the live tree out of their house and get it on the curb,” Denette said. “Don’t leave it in the garage or anything; get it away from your house.”

All homes should also have working smoke alarms and a fire escape plan, she said.