Authorities said Mariano's sister, 28-year-old Marion Mariano, was also severely burned. She and the little girl, named Eden, were airlifted to Maricopa Medical Center's burn unit in Phoenix.
The girl had facial and torso burns covering more than 40 percent of her body and was listed in critical condition late Friday, Villar said. Marion Mariano was burned over 17 percent of her body and was in critical but stable condition, she said.
A fourth victim, a man in his 40's or 50's, suffered minor injuries.
The home is located on a state highway and among several used by workers on a nearby farm.
Villar spent about three hours talking to the boy, Jalen, after the fire. He told her his mother had helped them to the doorway and that he had guided his sister outside before the girl fell and their uncle helped them to safety. The uncle had been working in nearby fields when the fire broke out at about 8:30 a.m. He saw the flames and rushed to the home.
The man tried going into the home to reach the children's mother but the flames were too intense. Villar said there were several vehicles parked about 50 feet away from the home and the sides closest to the flames had melted.
Investigators have determined that the fire started when a candle that had been sitting on a hutch inside the home was knocked over.
The family did not have insurance. A memorial fund has been established at Wells Fargo bank.
Villar described the family as being very close. Just a few weeks before the fire, Michelle and Marion Mariano dealt with the death of their grandfather.
"It's a very tragic time for this family," Villar said.