The death toll from a fire that tore through a warehouse hosting a late-night dance party jumped to 30 on Sunday as firefighters painstakingly combed through rubble for others believed to still be missing.

Only a fraction of the charred remains of the partly collapsed structure had been searched, and crews clearing debris were expected to find more bodies as they advanced, Alameda County Sheriff’s Sgt. Ray Kelly said.

Anxious family members who feared the worst gathered at the sheriff’s office to await word on their loved ones. They were told they may have to provide DNA samples to help identify remains.

The building known as the “Ghost Ship” had been carved into artist studios and was an illegal home for a rotating cast of a dozen or more people, according to former denizens who said it was a cluttered death trap with few exits, piles of wood and a mess of snaking electric cords.

“If you were going there for a party, you wouldn’t be aware of the maze that you have to go through to get out,” said Danielle Boudreaux, a former friend of the couple who ran the warehouse.

As many as 100 people were there for a party Friday night when the fire broke out just before midnight. Fire officials were still investigating the cause of the blaze, but they said clutter fueled the flames, there were no sprinklers inside and few exits to escape.

Boudreaux identified the operators of the Satya Yuga collective as Derick Ion Almena and Micah Allison. She had a falling out with Almena when she convinced Allison’s parents and sister about a year ago that the warehouse was a dangerous place for the couple’s three children to live.

The couple rented out five recreational vehicles and other nooks on the ground floor as living spaces. A rickety makeshift staircase led to a second floor where concerts were held. Former residents said there frequently was no electricity or running water.

Oakland planning officials opened an investigation last month after repeated complaints from neighbors who said trash was piling up and people were illegally living in the building zoned as a warehouse. An inspector who went to the premises couldn’t get inside, said Darin Ranelletti, of the Oakland Planning Department.

The city had not confirmed people lived there, but a former resident said she had been lured in part by reasonable rents in a region beset with a housing shortage and exorbitant leases driven by the tech boom.

Shelley Mack said she wasn’t told the residence was illegal until after she moved in a couple years ago and stayed for four to five months, paying about $700 a month. She said she was instructed to tell visitors it was a 24-hour workspace for artists and when outsiders or inspectors planned to visit, residents would scurry to hide clothes and bedding.

“It’s like a horror house. Just horrors in there,” she said.

Authorities declined to talk about the manager, saying they were focused on recovering the bodies and consoling families.

(AP)