Fire officials are investigating a second suspicious fire in as many nights, this time in the rear of an auto repair shop.

Crews were called to the back of the California Auto Clinic at 1593 Lauzon Road around 3:30 a.m. Wednesday.

"There were fire trucks everywhere, the road was blocked off," says owner Roger Dowhan.

Though the arson unit has not been called in to investigate, the incident commander has deemed the fire suspicious.

"Someone's trying to deliberating sabotage my business,” says Dowhan. “I'm here to make a living and take care of my family.”

Windsor fire officials say the fire started at the back of the property, where used oil filters and tires are stored.

 “Used oil filters, filled with oil. There's some kind of paper product in the oil filters, easy to ignite,” says chief fire prevention officer Lee Tome. “Once it gets going, it'll go pretty good."

Damage is estimated at $8,000.

Crews were also called to a suspicious clothing store on Tecumseh Road East early Tuesday morning after a fire started in some garbage left at the rear of the building. That fire also remains under investigation.