WINONA, Minn. -

Parts of Third and Center streets in Winona are still closed off as investigators look into what might have caused a devastating fire.

Firefighters were called to the 100 block of Center Street at about 2:00a.m. Friday.

Crews battled the flames for seven hours. It destroyed at least three buildings and damaged several others.

Officials say foul play is not suspected and they believe it started in the Islamic Center, where the fire had been burning the longest.

They say finding the exact cause will take time.

“(They will have to be) Digging through rubble piece by piece,” said Britt Hendrickson, assistant chief of the Winona Fire Department. “They're looking for a source of origin, so it's a very tedious and arduous task. It will take them at least today.”

Some of the businesses affected by the fire went straight to work Saturday morning cleaning up.

“I can't sit still,” said Amy Jo Marks, owner of Blooming Ground Coffee House and Pretty Things on Third. “So, I gotta do something.”

After Friday's fire, she's spending the day cleaning.

“The power's been out, so everything that's been refrigerated has been spoiled,” said Marks. “So you can't use it.”

Her two shops on the corner of Third and Center streets were among the luckier ones affected by the fire.

“Everything just has a layer of soot on it,” said Marks. “I don't have water damage at Blooming Grounds, which is great. Pretty Things had a little water damage. Stuff is a little damp, but just a lot of soot.”

Friends, family and even community members have stopped to help with things like documenting everything inside for the insurance company.

Firefighters worked for hours on Friday to save Paul Brosnahan's law firm building.

“I don't expect that it's going to be repairable,” said Brosnahan.

He said he’s grateful the majority of paperwork he handles has been backed up electronically.

Other businesses and lawyers have offered him temporary locations to meet with clients.

“If we meet with them it might be at their kitchen table instead of my conference room, but I should have a conference room probably by Tuesday or Wednesday,” said Brosnahan.

It will be a while before these businesses fully recover, but the business owners say the community support is what's keeping them going.

“It's just going to be a lot of work, but we have a lot of friends and a lot of great people helping,” said Marks.

Marks said she has two locations in Winona. She said while the one on Third Street is the busier of the two, her customers have been making trips to the other location to offer their support.

Brosnahan has been in contact with the three tenants living in the apartment above his business. He said they've all secured other living arrangements.