Crews face a large commercial structure fire, and investigators say it was set on purpose.
Crews allowed the blaze to burn near Kettering University in Flint.
It started around 6pm Saturday.
No one was inside.
Investigators say the structure had been vacant for the last five to seven years.
Flint Battalion Chief Theresa Root says, "It's just a little harder when we receive a commercial vacant structure fire because of the intensity, the heat, the smoke for the surrounding neighborhoods. It's just a lot more work."
No one was injured in the fire.
Witnesses say they saw three people walking away from the building.
