Oakland, California (CNN) After a day's worth of investigations, Oakland authorities were continuing to search for answers on Sunday regarding the fast-spreading deadly fire that engulfed a warehouse during an electronic dance concert.

They want to know about the rickety stairway. They want to know about the lack of permits. They also want to know: Could this tragedy have been avoided?

At least nine people died in the fire as scores of others escaped Friday night. But the fates of more than two dozen people were still unknown Saturday evening one day after the blaze that gutted the two-story warehouse.

Friends and family used every available tool -- phones and social media among them -- in the frantic effort to find out whether their loved ones were alive. People like 27-year-old painter Bob Mulé, who lost his friend to the fire, were left to grapple with the nightmare of that fiery night.

"I felt my skin melting," Mulé said. "I tried to save my friend but I had to leave him."

The Oakland Fire Department fears the fire may have burned up to 40 people in a structure that housed artists' studios and stored so many things that the housing department had notified property owners of violations for trash and debris.

'You could feel the heat of the flames'

By the time John Evanofski arrived at 31st Avenue, where an electronic music DJ known as Golden Donna was scheduled to perform, giant flames lit up the night sky amid the billows of black smoke.

"You could feel the heat of the flames," he told CNN. "Most of us were crying or unable to react. It was so hot and so terrible knowing that so many of us were still inside."

Freelance journalist Sam Lefebvre said many people were just getting there as the fire started since the dance party was supposed to go very late.

Alameda County Sheriff's Sgt. Paul Graves said 40 out of an estimated 100 people may have died. However, he cautioned that some people may have ended up at hospitals or made it out alive with friends. Later on, officials said the death toll might be in the dozens.

Initially, authorities recovered nine bodies and rushed their fingerprints to a lab in an attempt to identify the victims, an Alameda County Sheriff's Office coroner spokesman said.

Oakland Fire Chief Teresa Deloach Reed said emergency responders found most victims on the second floor given that the pallet stairway had become inacessible.

Evanofski was one of the lucky ones in a building filled with artists. His friend, who did nails, wasn't as fortunate, he said.

"She is one of the most magical people I've ever met," he said..

'Immense tragedy'

Calling the fire an "immense tragedy," Oakland Mayor Libby Schaaf pledged to get a "full accounting" that could be shared with the public as quickly as possible.

There was another question on authorities' minds: How did the first start in the first place?

The building is a "sort of live/work art space with a lot of old decorations and furniture," Lefebvre, the freelance journalist, told CNN. Photos posted on a blog showed elaborate wooden structures inside the building before the fire. Some of them include beds and living room furniture.

Reed described the interior as one that had partitions that divided space among several artists. She said she has heard reports that some people may have been living there but it remained unclear how many people lived there.

"Inside is just a wide assortment of just ... everything. Furniture, mannequins, statues. Just a lot of stuff inside," she told CNN.

Darin Ranelletti, Oakland's interim director of planning and building, told reporters Saturday the city had only approved permits for the building to be used as a warehouse -- not for residences.

City officials also had not signed off on a special permit for the event, Ranelletti said.

Last month the warehouse property owners had received notification of code violations for hazardous trash and debris, property records show. Officials had not yet completed an investigation into a November complaint for an illegal interior building structure..

A city inspector tried to enter the warehouse November 17 but was unable to make a visual inspection inside, Ranelletti said.

In addition, firefighters found no evidence of sprinklers in the warehouse.

CNN has reached out to the property owners for comment. Johnna Watson, Oakland police spokeswoman, said the building is not deemed a crime scene but it is still early in the investigation.

'It's too unsafe' for emergency responders

To find loved ones, people used the event's Facebook page Saturday to post names of potential show attendees. For those who survived, they also shared their names to show they were safe.

Twenty-five people are unaccounted for, as reported by people who either escaped the fire or believe they knew someone who was there, Reed said.

Photos: Oakland warehouse party fire A fire breaks out Friday night, December 2, during a party at a two-story warehouse and artists' studio in Oakland, California. Initial reports indicate dozens of people were in the building when the deadly blaze started, the Oakland fire chief says. Hide Caption 1 of 7 Photos: Oakland warehouse party fire The scene as firefighters battle the blaze from video footage by @Oaklandfirelive early Saturday, December 3. Hide Caption 2 of 7 Photos: Oakland warehouse party fire Firefighters begin to assess the scene of the warehouse fire on December 3. Hide Caption 3 of 7 Photos: Oakland warehouse party fire Firefighters have not been able to search the entire building, the fire chief says. Hide Caption 4 of 7 Photos: Oakland warehouse party fire Crew will remove debris and make sure the warehouse is safe for searching. Hide Caption 5 of 7 Photos: Oakland warehouse party fire Firefighters clear an entry to the smoldering warehouse. Hide Caption 6 of 7 Photos: Oakland warehouse party fire Officials will begin investigating to determine the cause of the fire. The Alameda County Sheriff's Coroner's Bureau and the Arson Task Force were called to the scene. Hide Caption 7 of 7

Terry Lightfoot, a representative of Oakland's Highland Hospital, told CNN the hospital received two patients and one of them has been discharged. Lightfoot said he did not know the condition of the patient who remained hospitalized.

Firefighters have not been able to search the entire building, where the roof collapsed onto the second floor and parts continued down onto the ground level.

Crews, possibly with heavy equipment, first have to shore up walls and make sure the building is safe.

"There's limited access to the structure," Reed told CNN affiliate KRON-TV in San Francisco. "It's too unsafe. And not only that, there's a lot of heavy wood from when the roof caved in that's going to have to be removed."

'I had to let him go'

For Bob Mulé, the warehouse wasn't just the site of a large dance party, it was both his home and his community.

Mulé told CNN more than 20 people living in the warehouse, which he described as a "collective artists' community," paid rent and were all involved in the creation of the space.

On Friday night, Mule stopped upstairs to listen to some music he described as a "very tame setting." Afterward, he headed downstairs to work on a painting. From his studio, he smelled smoke, which led him to investigate the source.

After seeing the flames, Mulé ran to find a fire extinguisher. He found one, and tried to pull the pin, but struggled mightily. After a little while, he turned back to save his camera and laptop.

At that point, Mulé spotted a fellow artist who called out for help. Mulé suspected that heavy-set artist had broken his ankle after falling from the second floor. He tried to save him.

Before the fire, an undated photo from Google Earth shows the building at 1305 31st Ave. in Oakland.

"I was pulling him out," said Mulé, who sustained burns from the fire, later wrapped in bandages. "The flames were too much. There was too much smoke and ... I had to let him go."

More than 40 people gathered Saturday at Chapel of the Chimes in Oakland for a vigil. Organizers asked attendees to light a candle at the end of the service, saying flames caused pain and destruction "but tonight we light the flame for good and for peace."

Now, as loved ones await answers in the coming days, Mulé must wrestle with the reality of losing a friend he couldn't save and the likelihood that the official deatTheh toll may climb.

"I'm glad I'm alive," Mulé said.