A burning candle started a building fire that killed four people and displaced dozens more in Oakland, city officials said.
The disclosure ruled out arson as the cause of the Monday blaze in the three-story building for recovering addicts and people who had been homeless.
Erica Terry Derryck, a spokeswoman for Oakland Mayor Libby Schaaf, declined further comment.
An investigation into the blaze should be completed within weeks, according to a press release from the city Thursday.
The fire occurred after city officials promised to crack down on substandard housing when 36 people died in a December blaze at a warehouse known as the Ghost Ship that had been illegally converted into live and work spaces for artists.
The latest fire occurred three days after city building inspectors found multiple fire code violations, including inoperable sprinklers and alarms, at the building that housed about 80 people.
Officials also noted a lack of fire extinguishers and overloaded electrical cords during the inspection that was prompted by a referral from firefighters who responded to an unspecified call in February.
The owner was given 30 days to correct the problems.
Residents described a filthy place where maintenance was neglected and trash piled up.
The building owner was trying to evict the organization that leased two of the building's three floors.