Advance Building Fire: Why did Southfield building catch fire?

(FOX 2) - Why did the Southfield Advance building catch fire?

That's been on the minds of commuters, emergency crews, and the city of Southfield, who have yet to get a good look at the structure, located at 9 Mile and Greenfield.

Big picture view:

A 911 call earlier in March alerted authorities that a fire was spilling out of the Advance building in Southfield.

Security called the dispatch center about a blaze at 2:42 a.m. It continued to build until fire crews moved in and put it out.

That was weeks ago. Because the building is structurally unstable, figuring out the cause of the fire has been a top priority for crews, but not one that the city could get to.

"It's significant fire damage on the third, fourth, and fifth floors — structurally unstable," said Chief Joey Thorington. "We have an engineering company who came in. They assessed the building, and now we have contractors in there. They just began shoring up the building today and we're not sure how long it will take."

Thorington added that one of the city's firefighters fell through the fourth floor after the ground collapsed.

When the building is made stable, the real investigation will begin.

"Once they are done, our fire department will go in and do their investigation along with all the insurance companies and their investigators," said Thorington.

Dig deeper:

The fire has also been a large inconvenience for the several businesses that operate inside.

One business owner said the closure has created all kinds of issues.

"It was devastating," said Rayford Frye, of Black & White Look Optical CEO. "We have an optometric office. We have ophthalmologist, optometrist, and opticians working there as well. All of our patient's things are locked up.  The glasses to be picked up. The insurance to be billed, all of our equipment."

There is security outside the building to ensure no one gets in.