Marvin Heemeyer

Marvin John Heemeyer (October 28, 1951 – June 4, 2004) was an American welder and an automobile muffler repair shop owner most known for his rampage with a modified bulldozer which is known as the Killdozer. Outraged over zoning disputes, he armored a Komatsu D355A bulldozer with layers of steel and concrete and used it on June 4, 2004 to demolish the town hall, the former mayor's house, and other buildings in Granby, Colorado. The rampage ended when the bulldozer got stuck in the basement of a Gambles store he was in the process of destroying. Heemeyer then killed himself with a handgun.

Heemeyer had been feuding with Granby officials, particularly over fines for violating city ordinances and a zoning dispute regarding a concrete batch plant constructed opposite his muffler shop.