PHOENIX -- Fire crews spent the early morning hours battling a fire at a Julioberto's Mexican Food restaurant in central Phoenix Tuesday
Somebody driving down McDowell Road spotted flames shooting from the drive-thru window at about 4:15 a.m.
That person called 911 and a first-alarm assignment was called out. Within minutes, dozens of firefighters converged on the restaurant on McDowell Road just east of 32nd Street.
Crews believe the fire started in the kitchen, saying an electrical spark from a malfunctioning deep fryer might be to blame.
Firefighters said it's not uncommon for restaurants like Julioberto's to leave their deep fryers on overnight. They suspect that the ventilation system was clogged with grease.
Once the deep-fryer sparked, that grease fed the fire. At one point, flames tore through the roof the building.
Crews knocked down the fire quickly, but not before it did extensive damage to the inside of the building.
Investigators will remain on the scene to determine if their initial suspicions about the deep fryer are correct.
Although Julioberto's advertises 24-hour drive-thrus, the restaurant was closed when this fire started, according to the Phoenix Fire Department. No injuries were reported.
According to the Julioberto's website, the 32nd Street and McDowell Road restaurant is one of nine locations in the Valley. There is a 10th restaurant in Marana.
McDowell Road was blocked at 32nd Street while firefighters dealt with the fire and mop-up operation. It was back open by 6:30 a.m.