Norwich Fire was dispatched around 17:00, 401 North Main St. Kleemann Auto for a reported fire in the building, Eng 2 which is about 400' up the road reported heavy smoke coming from the building, and dropped a feeder into the rear of the building. A 2nd alarm was requested, with a 2nd tower requested. Heavy fire broke threw the roof and caused a quick collapse of the South East end of the work bay, Crews worked the fire and command called 3rd alarm. After about a hour, the fire was darkened down, and crew worked to extinguish the stubborn pockets of fire. Crews remained on the scene for several hours for overhaul. Norwich investigation unit is on scene.