>> while the residents flee, trainor tries to determine who is unleashing this wave of destruction. >> we were notified that the individual who was driving this bulldozer was most likely marvin heemeyer. >> marvin was a commoner around town. he was well known. people knew him. many people considered him a friend. >> i met marvin heemeyer back in the 1990s. he ran a muffler shop in the town of grandby. and knew him just as a businessman. >> the motive is becoming clear. heemeyer's been harbored deep-seeded grudges against some prominent town members. this is his revenge. >> marvin heemayer was upset because a showman by the name of cody wanted to open a concrete batch plant adjacent to his muffler shop. mr. heemeyer felt this was not good for his property values and objected very strongly to the special use permit and the