SAN JOSE — A fire that severely damaged a KFC restaurant in North San Jose could be suspicious because the blaze apparently started in the dining room, not the kitchen, and there at least one report someone might have thrown something through a window prior to the 911 call, authorities said.

The fire was first reported at 4:27 a.m. at the KFC on Cropley Avenue just east of North Capitol Avenue. Responding crews from the San Jose Fire Department arrived to see “pressurized smoke” emanating from the front dining area of the restaurant, fire Capt. Mike Van Elgort said.

A second-alarm was called after firefighters feared they would not be able to get inside the building due to the penetration of the fire, but they were eventually able to safely enter and continue their extinguishing efforts.

Firefighters knocked down the blaze around 5 a.m. and had it fully out by 6:30 a.m., Van Elgort said. The building was unoccupied at the time, and no firefighter injuries were reported.

Van Elgort noted some unusual elements with the fire.

“It’s a little bit suspicious in that the fire started in the dining area,” he said. “We also have third-hand reports that something was thrown through the window.”

Fire investigators are examining the site, and a precise cause is still being determined.