A preliminary investigation into the north Minneapolis house fire that killed three young children in early October has found that their mother was not home at the time of the blaze.

Fire investigators said Monday they are ruling out arson as the cause of the early morning fire, but they are still trying to determine where the mother of the children, Taneisha Stewart, was at the time.

Authorities do "not believe Ms. Stewart was present inside the home at the time of the fire," Police Sgt. Sean McKenna wrote in a search warrant application filed Friday in Hennepin County District Court, which also noted that she had been drinking that night. "The lack of a competent adult inside the home with three sleeping juveniles under the age of seven is a factor" in their deaths.

McKenna, a longtime arson investigator, said in an interview that authorities determined almost immediately that some aspects of Stewart's story didn't make sense.

She had said she was sleeping when the blaze started and tried to save the children but was driven back by flames and dense smoke inside the house in the 2700 block of Penn Avenue N. But McKenna said that when authorities arrived shortly after midnight on Oct. 4, Stewart was "not dressed in sleeping attire" and an on-the-scene investigator noted the absence of soot on her clothes and that she smelled of alcohol.

He also said it was unusual for Stewart to have emerged from "a structure that's filled with enough smoke and heat to kill three people" with "no singed hair." She did not require any emergency medical assistance.

"I don't believe she was in the home; I do believe she arrived home to find the fire fully involved," McKenna said. The blaze caused about $150,000 worth of damage, he said.

Stewart could not be reached for comment Monday.

Pastor Harding Smith, who has served as a spokesman for the family, declined to comment until he speaks with Stewart, who just moved to Minneapolis from Chicago. Smith said that Stewart's account of the fire had remained consistent.

"My focus right now is laying these kids to rest," Smith said. "These kids are innocent, and my priority and my goal is to make sure these kids get a proper burial."

Smith said he would make a more complete statement after the funeral. He declined to comment on the rest of the family's reaction to the findings.

Funeral services Latorious, 6, Latoria, 5, and Latorianna Thomas, who was about to turn 2, are expected to be held at 11 a.m. Saturday at Spiritual Church of God, 3978 W. Broadway, in Robbinsdale.

Stewart, who moved into the rental property on the day of the fire, has said previously that the furnace did not work when she tried to warm the house. With the temperature dipping, Stewart turned on the stove so her family could keep warm.

Investigators have concluded that the electric stove caused the fire, but they are still trying to pinpoint the exact cause.

McKenna said that a preliminary investigation suggested one of two possibilities: "radiant heat" from the stove set a nearby wall on fire, eventually spreading to the rest of the house, or the heat ignited oil dripping from a frying pan on the range that had been used earlier that evening to cook a meal.

Firefighters arrived to find the two-story frame house consumed with fire and heavy smoke as they tried to reach a rear bedroom, where a 911 caller said the children were "trapped," according to a scanner recording posted on MN Police Clips.

The blaze, which was reported shortly before midnight, apparently started on the ground floor, before spreading to the roof, according to scanner traffic and fire officials.

While searching the structure for survivors, firefighters found Latoria Thomas at the top of the stairs with a faint pulse. They tried to revive her at the scene and transported her to Hennepin County Medical Center, where doctors were unable to revive her. Her two siblings were pronounced dead at the scene.

Chuck Laszewski, a spokesman for the county attorney's office, declined to comment Monday on the possibility of criminal charges against Stewart because the police are still investigating the incident.

On Monday afternoon, an impromptu memorial of teddy bears and candles had been taken down, replaced by a single potted flower resting in the charred remains of the house's foyer. Handwritten messages scrawled next to boarded-up windows urged the victims to "Ball out in Heaven" and "Rest Up My Babies."

Fire deaths have fallen nationally in recent years, thanks to more homes being built with flame-resistant materials and safety improvements such as smoke detectors and sprinklers.

City fire officials say that 45 people, 23 of them children, have died in "mass casualty fires" — in which at least three people are killed — since 1980. There have been four such fires in Minneapolis in the past five years, officials say, including one on Valentine's Day 2014, when five children were killed after a North Side duplex went up in flames.

"I feel badly for the firefighters, I feel badly for Ms. Stewart, I feel badly for the neighbors," McKenna said Monday. "It's just the story we have been given is not accurate."