Onlookers were flabbergasted Wednesday night as fire ravaged the back of DeKalb’s second Wendy’s restaurant, 1321 Sycamore Road, less than a week after the other on West Lincoln Highway went up in flames.

“I heard it on the scanner and couldn’t believe it,” Sycamore resident Geoff Cockrum said. “I said, ‘You’ve got to be kidding me.’ So much for rebuilding the other one right away.”

Area fire and police officials again believe overheated grease to be the cause of the fire, which was reported in a 911 call from Wendy’s managers shortly after 10 p.m. Several managers standing outside the Jewel-Osco parking lot across the street refused to expand on the details of the fire.

DeKalb Cpl. Tom Petit said officials believe the fire started in the kitchen’s deep fat fryers. By the time police arrived, firefighters had contained the blaze but saw flames shooting up the vents and had to keep backing off the roof of the restaurant.

Police quickly closed Sycamore Road to through traffic between Hollister Avenue and Oakwood Road, covering the street with flares to make room for three fire trucks and additional police cars. Although the fire was put out, a thick stench still hung in the air, and Wendy’s closed by 11 p.m.

No injuries were reported. Police said managers inside the restaurant when the fire started were evacuated immediately.

The fire follows another overheated grease fire at Wendy’s restaurant, 1115 W. Lincoln Highway, that occurred before 10 p.m. Friday. That fire also started in the deep fat fryer unit, causing an estimated $250,000 in damage.

The fire is DeKalb’s third in the past week, the other being an apartment fire at 916 Market St. The cause of that fire is unknown.