SYCAMORE – Hundreds of people lined the sidewalks and watched helplessly Monday evening as a fire destroyed the St. John Evangelical Lutheran Church in Sycamore. Two firefighters were injured.

Sycamore firefighters were called to the church, 327 S. Main St., shortly after 5 p.m. Firefighters saw smoke coming from the 66-year-old stone church, but no flames. Sycamore fire officials decided to open a hole in the church to clear the smoke, Sycamore Lt. Duane Prather said. When they did, the church exploded.

The roof blew off the church and the sky filled with 40-foot flames, Sycamore Fire Chief Bill Riddle said.

“In my 25 years, I have not seen a building blow up like that,” Riddle said.

The blast propelled two firefighters across an alley adjacent to the church and blew out some of the church’s stained glass windows.

One firefighter suffered a broken leg and was transported to OSF Saint Anthony Medical Center in Rockford. Another was treated and released from Kishwaukee Community Hospital with a burned hand. Officials have not released the names of the firefighters.

This was the second fire at the church in two days.

Sunday morning, during church service, the Rev. Donald Phelps evacuated the church when smoke was reported in the basement. The Sunday fire, which started in the pipe organ, was unrelated to the Monday evening fire, Riddle said.

The 1938 church looked like a cathedral, with solid-wood pews and walnut beams, church member and Sycamore 1st Ward Alderman Cheryl Maness said.

The church had stained glass windows worth $1 million that were uninsured, Maness said.

“I was baptized here, confirmed here, married here … My parents married here. It’s sick,” church member Becky Springer said.

Prather said 60 to 70 firefighters from 11 communities responded to the fire. They fought flames for more than four hours.

Dozens of fire trucks and emergency vehicles crowded the streets in the residential area surrounding the church as bystanders navigated snowy yards and intertwined fire hoses. Residents gathered, some crying, while orange-tinted smoke and mist drifted from the scene.

Nancy Brown, a Sycamore resident, who lives across from the church, said she was standing on the sidewalk trying to determine where the smoke was coming from when she heard the explosion.

“It was unbelievable,” Brown said. “My daughter was crying.”