The fire quickly consumed the building, which was built in 1930 and was once a milk bottling plant, even though there was a fire station less than 200 yards away. A local newspaper, The East Bay Times, won a Pulitzer Prize for its coverage of the fire, which “exposed the city’s failure to take actions that might have prevented it,” according to the prize committee.

In closing arguments, the prosecutor called the warehouse a “death trap,” and dismissed the defense’s claims that arsonists might have been responsible for the blaze. Witnesses had testified that there were no smoke alarms or sprinklers, and that Mr. Almena once laughed off the suggestion that the warehouse was dangerously susceptible to fire.

The grief of family members of the victims, many of whom packed into an overflow room during the proceedings, permeated the trial, with the prosecution reading the names of each of the 36 people who died, and showing final text messages from victims, saying goodbye to loved ones before they perished.

“I can just be at home, and all of a sudden I cry, thinking about something,” David Gregory, who lost his daughter, Michela, in the fire, told The Los Angeles Times. “I come to court — at least I’m learning what’s going on. I’ve been committed to coming to learn everything, as much as I can, about this case. I want answers.”

Lawyers for Mr. Almena and Mr. Harris built a defense that cast blame for the fire on the landlord, and on city officials who had visited the property over the years and had never condemned it as a fire hazard. Investigators never determined the exact cause of the fire, but it was widely suspected to have been ignited after an electrical malfunction.