A fire Monday night at the Blue Knob Auto Service Center in Duncansville, is now believed to have been intentionally set. Investigators now have arrested a suspect who they believe torched the business. 43 year old Nathan Hall is facing felony charges, including arson. Hall is now behind bars in the Blair County Prison with bail set at $100,000 cash. Fire investigators have determined that the blaze got its start in the rear of the building Monday night just before 11:30. Nobody was hurt, but the damage to the building has now been estimated to exceed one million dollars. Hall was an employee of Blue Knob Auto Service Center for 10 years. Security cameras caught him entering the building and pouring oil onto the garage floor, followed by flames appearing in a room where Hall exited from.