PHOENIX - Investigators are working to determine what started a fire in a North Phoenix restaurant overnight.
Phoenix fire Capt. Jonathan Jacobs said the blaze at a Carls' Jr. near 35th Avenue and Bell Road was reported around 11:40 p.m. Tuesday.
The first crews found flames pouring from the roof of the restaurant and upgraded the call to a first alarm.
Jacobs said the fire was mostly contained to the attic and roof area.
The restaurant was closed but there were workers inside doing construction work, Jacobs said.
No one was injured.
Jacobs said there is heavy damage to the building and the roof would likely continue to collapse with the weight of the water used to put out the fire.
Investigators are now looking into the exact cause of the blaze.