Firefighters were called to a southwest Atlanta auto repair shop before daybreak Thursday to douse a second suspicious blaze in about six hours.

Atlanta fire Capt. Jim Trainor said several small fires were set just before midnight Wednesday inside Pro One Auto on Campbellton Road just north of Fort McPherson.

Those fires caused minor damage to the building, and Trainor said crews used thermal cameras to make sure the fires were out before leaving the scene.

Firefighters were called back to the garage around 5 a.m. after another blaze broke out.

“Someone has come back and worked hard to make sure more damage was done,” Trainor said. “We’re very confident that this was regenerated by someone’s actions.”

The second blaze caused extensive damage to the roof of the building.

No injuries were reported.

Campbellton Road was shut down between Lorenzo and Venetian drives for much of the morning commute.