2:45 p.m.An early morning fire today killed a Napa grandmother, her boyfriend and two of her grandchildren.

Aurora Castanon, 58, Eutimo Torres, 37, Giovanni Mendez, 4, and Matthew Castanon, 12, were found unconscious about 5 a.m. inside the same bedroom of the home in the 1400 block of Vale Avenue near Silverado Trail.

“The victims were in different places in the room. We don’t know if they were all in the bedroom when it started of if they gathered in there after the fire started,” said Napa Fire Capt. Scott Sedgley. The bedroom is adjacent to the living room where the fire started and where the majority of fire damage occurred.

The two adults and the 4-year-old were pronounced dead at the scene. The 12-year-old was taken to Queen of the Valley Hospital and declared dead on arrival.

The victims most likely died of smoke inhalation, Sedgley said. “Smoke inhalation can knock a person out in seconds.”

At this point, fire officials do not have a cause for the blaze.

Castanon’s grandchildren lived at her house from time to time, according to neighbors. Matthew was a student at Alta Heights Elementary School.

The Napa/Solano Counties Arson Task Force was on scene for the majority of the day looking for clues to determine how the fire started, Napa Fire Capt. Jim Pope said.

Matthew Castanon’s father arrived at the scene in the early afternoon. The boy was pulled from the burning home and paramedics administered CPR while he was rushed to the Queen.

A neighbor, who did not give her name, said Aurora Castanon lived in the house for about 10 years.

“She was a professional housecleaner. I talked to her yesterday. She told me she has been really cold the past few weeks because her heater hasn’t worked for about three years,” the woman said. “We were not anything like good friends, but I used to see her all the time and we would chat. I just feel numb about all of this.”

A neighbor across the street said his stepson was friends with Matthew Castanon.

“They used to play together all the time. Her grandkids didn’t live with her, but they were at her house like spending the night very frequently,” the neighbor said. “She (Aurora) was a really nice person. A great neighbor. They were good people.

“I was sleeping when I heard what sounded like something hitting the side of the house. I got up and saw a neighbor banging on the door (of the house that was on fire.) It was then I could see the flames shooting out from the front windows,” he said. “This is just a terrible tragedy. I can’t believe it.”

This is the worse fire fatalities to hit Napa since January 1999, where a house fire on Yajome Street killed a Napa mother, her 2-year-old daughter and her 5-week-old nephew.

The area is sealed off from the public, except for residents who live there.

Autopsies for the four victims are scheduled for later today.

Check back here for more updates throughout the day.