BRIDGEPORT — The deaths of a mother and her two young sons in a Colorado Avenue house fire in February have been declared murder by arson.

The official finding that the blaze had been set was made as a result of a joint investigation by the Police Detective Bureau, Fire Department Arson Squad and State Police Fire Marshals, police Lt. James Viadero said Friday.

No arrests have been made in the case.

"Today, they classified it as arson," Viadero said. "It will be three arson murders. The investigation is continuing."

The fire erupted about 10:30 p.m. Feb. 25 at 601 Colorado Ave., a 1920s Victorian house, killing Tanechia "Sophia" Blackwood, 27, and her two boys, 5-year-old Elijah Boyd and 5-month-old Dwayne Dennis, as they slept in their first-floor apartment.

The three-family house had only one smoke detector, and that was broken at the time. The room where the mother and children were sleeping was not damaged by the fire, but their deaths were caused by asphyxiation from smoke and carbon monoxide, a city fire inspector said.

Robert Blackwood, the home's owner and the woman's father, could not be reached for comment. He also lived in the house.

Three days before the fatal fire, a Superior Court judge allowed Blackwood's mortgage company to foreclose on the house.

Robert Blackwood had gone to the store before the fire started, and returned to see the home engulfed in flames.

The spot in the house where the fast-moving fire ignited — a kitchen and porch on the first floor — "was a ball of flames, so badly burned," acting Fire Chief Brian Rooney said previously.

Tanechia Blackwood had escaped a blaze exactly 10 years earlier, and her father had helped several children out to safety. That fire was also set, according to the woman's aunt.

Anyone with information about the Feb. 25 fire is asked to call the police tip line at 1-800-978-2828. All calls will be treated confidentially.

Aaron Leo, who covers regional issues, can be reached at 330-6222.