Claire Franklin Pierce, 61, was arrested in connection with a June 7 fire at the donation center of Gospel Rescue Mission in South Tucson.
Pierce was booked into Pima County jail on suspicion of arson of an occupied structure and felony criminal damage, said Lt. Jeff Inorio, a South Tucson Police Department spokesman.
The fire started about 3 a.m. at the Gospel Rescue Mission Donation Center in the 300 block of West 28th Street, near South 10th Avenue.
The fire spread to a building on the property and also damaged at least two vehicles. No one was injured.
During the investigation, a man of interest was identified as making threats to "set the place on fire", Inorio said. He said the man was detained shortly after the fire.
While the man was interviewed by investigators, he made statements of his involvement in the fire, Inorio said.