A former Tucson businessman was found guilty in federal court of possessing unregistered explosive devices.

Todd Russell Fries, 50, also known as Todd Burns, was found guilty Friday by a jury before U.S. District Judge Cindy K. Jorgenson.

Fries is set for sentencing Oct. 18, and faces up to 10 years in prison, and not more than a $10,000 fine, or both, according to a news release.

Fries, the former owner of Burns Power Washing, is currently serving more than 12 years in prison.

He was sentenced in March for launching a chemical attack on former customers who were not satisfied with work he performed on their driveway. The couple canceled their final payment of $200.

Buckets of chlorine tablets were mixed with chemicals and ignited in their front and back yards, resulting in a gas cloud the size of a football field. It caused the evacuation of homes in the northwest-side neighborhood, authorities said.

Federal agents who served a search warrant in 2011 at Fries’ home in connection with the chemical weapon’s investigation, found 24 explosive devices in a bedroom, states the release.