Special agent in charge of the San Francisco office of the Bureau of Alcohol, Tobacco, Firearms and Explosives Jill Snyder said Wednesday people on the second floor of the warehouse did not know there was a fire on the first floor until it was well developed. There were two stair cases from the first floor to the second floor, but neither of them led to a building exit.
Snyder said the smoke went up the stairwells to the second floor, trapping the victims.
Stay with Action News and ABC30.com for more on this story.