Authorities say it appears one person died and another is trapped after part of a roof collapsed at a mall in the Northern Ontario city of Elliot Lake.

They confirmed that news Sunday, a day after the roof-top parking lot gave way at the Algo Centre Mall, causing metal and concrete debris to come crashing through two floors of the shopping centre.

The Ontario Provincial Police's site commander said rescue officials using camera equipment to scour the wreckage discovered the person who is thought to have perished.

"We have obtained some visual information relating to a visual of a hand and a foot, which is our grounds for the suspected casualty in this case," said Insp. Percy Jollymore of the OPP. "We cannot confirm an identity, we cannot confirm anything about that. We just have a visual, and the location is such that we cannot approach it at this time."

Rescuers believe someone else is trapped in the debris, too, Elliot Lake Mayor Rick Hamilton said. That person seems to have tapped on the wreckage in response to shouts from rescuers.

"Examination of the scene continues to indicate that there's still a rescue," he said. However, because of the precarious condition of the site — an eight-metre-long steel-and-concrete I-beam weighing more than a tonne is among the collapsed material — it will likely be 10 to 12 hours before a rescue crew can get in, Hamilton said.

Jollymore said police still know of nine people who are unaccounted for. Names continue to be crossed off that list as members of the community account for their loved ones.

Initial reports said four people had non-life-threatening injuries and that no fatalities could be confirmed.

The collapse happened around 2:20 p.m. ET Saturday. There are reports two cars went through the roof. Twisted debris could be seen near a set of escalators, food-court tables and lottery kiosks.

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A woman checks out the damage after Saturday's roof collapse at the Algo Centre Mall in Elliot Lake, Ont. (Cora Richer/Canadian Press)

Elaine Quinte, who owns the Hungry Jack's restaurant in the mall, was working at the time and remembers walking through the debris.

"It happened so fast and my first thought was, I have to turn my gas off, I have a restaurant," Quinte said, adding she soon changed her mind and left.

"All of a sudden I started getting hit by some of the rubble. I turned around. I saw other people in the food court running out of the doors. I remember seeing the concrete. There was instantly so much dust, first you saw [the food court], and then you didn't."

The cave-in triggered a gas leak that prompted emergency officials to cut power to the centre in the community, 150 kilometres west of Sudbury.

Search for victims

Emergency crews worked through the night to try to find anyone stranded in the debris, and were expect to do so again Sunday night.

"It's just very unstable and unsafe for the crew to go in there. So we have to do a very slow and tedious, but safe, entry," explained Bill Needles, the incident commander from Toronto's heavy urban search and rescue team, which was deployed to help in the effort.

An information line has been set up at 1-888-310-1122 for members of the public.

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The portion of the roof that collapsed served as part of a rooftop parking area. (Submitted by Robert Dumais)

CBC's Mireille Langlois said 10 ambulances and five fire trucks could be seen outside the mall Sunday morning.

Witness Jean-Marc Hayward said he was left rattled by what happened.

"It felt like an earthquake," Hayward told CBC News. "It was like, I don't know, I'm still shaken up about it. It's really scary, very scary. First thing after it all happened, you're trying to take it in and next thing you know everyone is trying to get outside and one guy is saying, 'there's no way out, there's no way out.'"

Mike Mantha, the MPP for Algoma-Manitoulin, said he was "shocked and horrified" to hear about the collapse that occurred in the parking lot outside his constituency office.

"My thoughts and prayers are with those who are missing and injured during this tragic event," Mantha said in a statement released Sunday.

Structural study 'turned up nothing'

Rhonda Bear, the Algo Centre Mall manager, told CBC News that the mall has been doing repair and maintenance work on parts of its roof over the last year, but "there hasn't been any huge structural repairs" to the section of the mall that gave way. The portion of the roof that collapsed served as part of a rooftop parking area.

She also said that the owners of the mall, Toronto-based Eastwood Mall Inc., ordered an engineering and structural study on the nearly 30-year-old building, parking lot and adjoining hotel a month ago.

"It turned up nothing," Bear said.

In April, the Elliot Lake Standard newspaper published a letter by Bear saying that "the owners have been working very hard to bring the mall to good standing and rebuild the mall's reputation to a positive one."

Bear wrote in her letter that owners have poured $120,000 into mall repairs as part of a "facelift" project over the prior 12 months.

Asked on Saturday how crowded the mall was when the cave-in happened, Bear said it was less busy than usual for a Saturday.

'Plagued' with leaks

The Standard newspaper has previously reported that the mall had been "plagued" with leaks from the roof for years.

About four years ago, the mall's owners embarked on a $1-million overhaul of the roof to end the leaks, which were forcing merchants to shut their stores as well as damaging their wares. An architect on the project warned that if moisture accumulated in some of the fibreboard pads lining the roof's concrete slabs, the pads could deteriorate.

The newspaper also reported that part of the ceiling in a mall restaurant collapsed due to the leaks, and that the roof's patchwork of repairs was "easy to see."

In March, the mall's managers pleaded guilty in provincial court to having sprinklers and fire alarms that failed to meet the fire code. Management spent $50,000 to upgrade the fire-prevention infrastructure to avoid potentially heftier fines.

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A firefighter examines the damage from the collapsed roof of the Algo Centre Mall in Elliot Lake, Ont. (Mike Neely/Facebook)

With files from The Canadian Press