The Cook County State’s Attorney has charged an 18-year-old Riverside resident with aggravated arson after she reportedly set a fire inside the kitchen of the Oak Room in the basement of St. Mary Church, 97 Herrick Road in Riverside on April 9.

The church’s evening Palm Sunday service was just ending and officials estimate that about 150 people were inside the building when smoke in the lower-level Oak Room activated fire alarms.

According to Riverside police, parishioners who smelled the smoke went downstairs to find a cardboard box and some paper on fire on top of a stainless steel countertop in the Oak Room kitchen. The parishioners were able to push the material into a sink and douse it with water prior to firefighters arriving on the scene.

Parishioners evacuated the church and a grade-school volleyball team practicing in the nearby gym also evacuated the building. No one was injured.

At the same time, another parishioner told police that a teenager had been in the basement of the church just prior to the fire alarm sounding. Police located the teenager unlocking her bicycle at the bike rack in the church parking lot.

Police said the teenager had been involved in other incidents at the church, including theft, which were handled internally but never reported to police. The teenager reportedly confessed to setting the fire with a lighter, but Police Chief Thomas Weitzel said she “could give no reason for the arson. None whatsoever.”

Weitzel described the damage done to the kitchen as minor.

“It was not a raging fire by any means,” Weitzel said. “But parishioners could smell the smoke upstairs in the church.”

Fire Chief Matthew Buckley said firefighters used fans to clear the building of smoke and that parishioners were able to re-enter the building after a short time.

St. Mary Church Pastor Rev. Tom May on April 10 issued a special announcement to parishioners about the fire.

“We are fortunate that the fire alarm worked as intended and alerted the parish to the potential danger,” he wrote. “We are grateful no one was injured and that the damage was minor. We will continue to cooperate with the Riverside police.”