The most recent fire was reported at the church on Balch and Fourth just before 8 pm on Thursday, authorities say.
Officers arrived there for a report of a burglary but found a small fire and a suspect still inside.
Crews put out the flames and arrested 19-year-old Evan Regalado for setting the fire.
Arson investigators are still working to determine if Regalado is responsible for the fire on Thursday morning.
It occurred at about 9 am after someone broke into the building, and church staff spent the day cleaning up.
Church trustee Steve Whaite told Action News he thinks the fire was arson aimed at the church because they keep kicking drug addicts out of the building, including just hours before the fire.
"The one guy's been breaking into the church for months now," he said. "We find out where he's breaking in and we put up bars and then he breaks in different places and we put up more bars."
Grace United won't be opening for services this weekend because its congregation is mostly older, but they're making plans to reopen in the coming weeks.