The airplane was destroyed when it departed controlled flight during a go-around/balked landing at about 1450 Mountain time and impacted a parking lot and industrial building. Visual conditions prevailed. The Private pilot, the sole occupant, was fatally injured. Witnesses said they heard an engine sputtering or backfiring as the airplane passed overhead. On final approach, the airplane was too high and too fast. One witness said one of the propellers was windmilling; another said the left propeller was not turning. At some point past midfield, the pilot applied power as if to go around. The airplane rolled steeply to the left, descended, crashed into a parking lot and exploded.