The death toll from a blaze that engulfed a converted warehouse during a dance party in Oakland, California, has risen to 36 – the greatest loss of life from a US fire in over a decade, as searchers sifted charred ruins being treated as a crime scene.

Authorities say they are certain to find more bodies in the gutted building and were still trying to account for about 50 people reported missing by loved ones, while ruling out any drastic climb in the tally of deaths.

“If you have a best friend out there, please hug your best friend,” Franchesca Dickerson, a 21-year old hairdresser, told a candlelight vigil, as she held a collage of images of a friend who died in the blaze.

“I’d give 50,000 years to hug mine,” added Dickerson, who was to have joined her childhood friend, 19-year old Michalea Gregory, at the party, but changed plans because of work.

Brian Hough holds a photograph of his son Travis, who was among the deceased at the warehouse fire, during the vigil in Oakland, California, US. (Photo: Reuters)

The cause of the fire, which erupted late on Friday in a sprawling two-story building leased to an artists’ collective, has yet to be determined.

Officials have said arson was not immediately suspected. But charges ranging from involuntary manslaughter to murder could feature in a potential criminal case, Alameda County District Attorney Nancy O’Malley told a news conference.

Possible safety violations were expected to be one aspect of the investigation, with city officials having said the site was already under investigation for reports of illegal construction.

Investigators from the US Bureau of Alcohol, Tobacco, Firearms and Explosives identified an “area of interest” on the ground floor that was still out of reach, said Sergeant Ray Kelly, a spokesman for the Alameda County Sheriff’s Office.

He described the spot as being at the rear of the warehouse, where makeshift studios and cubicles were clustered.

O’Malley said fire investigators and a task force from her office were working with recovery teams inside the wreckage to preserve any potential criminal evidence as they seek signs of victims and clues to the origin of the blaze.

Debris was being removed “bucket by bucket,” said Deputy Fire Chief Darren White, but a large construction crane at the scene required nearby electricity lines to be shut down for several hours, as a precaution.

– Reuters