State fire officials have finished their investigation into the cause of a New Year's Day fire in Warren that claimed the lives of a mother and her five-year-old son. 

Cassandra Gray, 34, was killed just after 3 a.m. after the fire tore through their Woodland Street home. 

Investigators said Gray and her son Otto were upstairs on the second floor and we not able to make it out of the home. 

 

They explained in their findings that Gray's husband Lee and another son, Simon, were asleep downstairs in the living room and were able to make it out of the home through the garage. 

Investigators found that the fire started in the back of the home and spread into the home. 

After speaking with Lee Gray, investigators were told that guests were over the night before to celebrate the new year and were placing their cigarette butts into a blue tote that had ashes from the fireplace outside on the back deck next to the sunroom. 

Gray later woke to the smell of smoke and discovered that a wicker basket he kept his kids' toys in had caught fire in the sunroom. 

Investigators said he went upstairs to wake his wife and his son Otto, then tried to put out the fully-involved fire with an extinguisher. 

When the extinguisher didn't douse the flames, he tried to get back upstairs, but investigators said the smoke was too heavy, so he escaped through the garage with Simon. 

Gray gave investigators video surveillance from his back patio that showed the blue tote on fire between the sliding glass doors into the sunroom and a pile of firewood located inside. 

Investigators saw that the bottom of the tote was melted into the patio wood and the flooring was consumed by fire around the tote. 

However, the assistant state fire marshal explained in his report the cause of the fire was undetermined, citing that "the careless use of smoking materials cannot be eliminated as a possible ignition source for this incident."

Warren Fire Chief Ken Nussle also told 21 News investigators found no smoke detectors in the home after the fire.  

"Every house in the city of Warren should have working smoke detectors on every floor in the home," said Chief Nussle. "They should be tested monthly to make sure, indeed, they are working and also make sure they have a 10-year lithium battery in them and not just a nine-volt battery in them to make sure they're going to work when needed."