The Sonic restaurant on Bend’s south end was destroyed by fire early Sunday morning.

The manager of the restaurant on S. U.S. Highway 97 called 911 at 6:34 a.m. after discovering the fire and escaping the building, according to the Bend Fire Department.

Fire crews responded and found heavy black smoke rolling out from under the roof of the building. Two ladder trucks and 21 total personnel mounted a defensive attack, but fire officials said the building was a total loss. Bend Police Department, public works workers and Cascade Natural Gas helped secure the scene.

The cause of the fire is under investigation.