The fire that killed 36 people during a dance party at an Oakland warehouse grew rapidly and was raging by the time people on the second floor of the building detected it, trapping them upstairs, investigators said.
Federal investigators provided the details Wednesday. With the death toll at 36, officials earlier announced that recovery efforts at the site have ended.
Jill Snyder, special agent in charge of the San Francisco office of the Bureau of Alcohol, Tobacco, Firearms and Explosives, said it appears the fire started on the first floor "and the occupants were consumed by smoke before they could get out of the building."
She said smoke traveled up two stairwells, trapping the occupants on the second floor.
The news comes a day after Oakland officials declared a local state of emergency. The Oakland City Council is slated to ratify the state of emergency Thursday. This will begin the process for state and federal aid.
A refrigerator was a potential source of the fire, but it was too soon to say for sure, said Snyder.
"We have no indication that this was intentionally set," she said.
Tearful family members visited the scene Tuesday and exchanged hugs hours after the founder of the arts collective that used the warehouse stood near the gutted building and said he was "incredibly sorry."
Derick Ion Almena said he was at the site to put his face and his body in front of the scene, but he deflected blame for the blaze, saying he signed a lease for the building that "was to city standards supposedly."
"Everything that I did was to make this a stronger and more beautiful community and to bring people together," Almena told the Today show on NBC.
The fire broke out during a dance party Friday night in the cluttered warehouse. It had been converted to artists' studios and illegal living spaces, and former denizens said it was a death trap of piled wood, furniture, snaking electrical cords and only two exits.
Almena did not respond to emails or calls to phone numbers associated with him by The Associated Press. He told San Jose television station KNTV that he didn't attend the event Friday night and that he and his wife had decided to stay at a hotel because he was exhausted.
City and state officials fielded years of complaints about dangerous conditions, drugs, neglected children, trash, thefts and squabbles at the warehouse, raising questions about why it wasn't shut down. The district attorney warned of possible murder charges as she determines whether there were any crimes linked to the blaze.
A building inspector who went to an Oakland warehouse Nov. 17 after receiving a complaint of illegal interior construction was unable to get inside and left.
Oakland Mayor Libby Schaaf said late Tuesday the inspector followed procedure and later sent a request to the owner to gain entry. She did not reveal the outcome of that request.
Under the Oakland city code, building officials and fire marshals need court permission to enter commercial lodgings if the owner or manager refuses access.
Building inspectors typically cannot force entry to a property unless there are pressing circumstances, said Schaaf.
Fire officials have started knocking down parts of the building, known as the "Ghost Ship," that they said were structurally unsound.
Alameda County sheriff's Sgt. J.D. Nelson said that of the 36 victims found, 35 have been identified and 20 of their families have been notified. Officials are still lacking any type of identity for one person.
Stories of the victims' last minutes, meanwhile, emerged.
Alameda County sheriff's spokesman Sgt. Ray Kelly said that some of the victims texted relatives, "I'm going to die," and "I love you."
Rescue crews found bodies of people "protecting each other, holding each other," said Kelly.