Federal agents are assisting Vallejo fire investigators to determine what caused the fire that killed three people including a baby, and extensively damaged a two-story house on Emerald Circle.
The fire broke out downstairs around midnight, and swept through half the house before firefighters arrived within minutes of being called.
"Apparently when we first got here in the originally in the morning there was a lady on the roof being helped down the ladder by some neighbors," said William Tweedy from Vallejo Fire Department.
She was hospitalized with smoke inhalation, and could offer little information about what happened.
"She basically said she was awoke by the smoke, and that the house was filled with smoke and she went out the window," said Tweedy.
Police said at least half a dozen people lived in the house. Only four were at home when the fire started. Amber Quiros said it was her mother who escaped.
"It's very sad it's something I'd never wish on anybody. I just want, I want my Mom to come home she works so hard," said the fire victim's daughter Amber Quiros.
She said her 11-month-old nephew was among the victims.
"He didn't even make it. Oh my God. He was so joyful and smart. I don't even know why, I don't understand why things happen. I guess this is our Merry Christmas huh?" said Quiros.
Sixty-year old Douglas Dykes and David Dykes, believed to be in his 50's were also killed. Police say they want to question a man they called a part time resident of the house.
"There's been some volatility between the family and the relationship with one of the family members and his connection here, so you know who knows if he had access to the home we can't eliminate anything at this point," said Lt. Richard Nichelman from the Vallejo Police Department.
At this point, nothing has been ruled out.