Fire crews arrived at the building, which used to be an IHOP restaurant, around 5:30 Saturday morning.
When they got there, they found some heavy flames and smoke tearing through the back of the building.
Crews put a quick attack on the building and knocked the fire down in minutes.
Firefighters are still on scene cleaning up.
Fire investigators say homeless people likely started the flames before they got out of control.
No injuries have been reported and crews are expected to be in the area for the next several hours, so you'll want to avoid that area.