Marvin John Heemeyer (1952 – June 4, 2004) was a skilled welder and owner of an automobile muffler-shop. On June 4, 2004, he destroyed a significant portion of Granby, Colorado, a small town in the U.S..
Heemeyer was born in South Dakota. He had disputes with various officials and individuals in Granby, particularly involving a zoning dispute which allowed a concrete factory to be constructed opposite his muffler shop, severely hindering him from operating his business.
Described by local people as very intelligent and an expert at welding, Heemeyer constructed an improvised 85-ton tank by welding two layers of steel armor sandwiched with concrete onto a 53-ton Komatsu D335A bulldozer (which was initially identified as a Caterpillar D9). His creation has been nicknamed "Killdozer".
In places, the vehicle's armor was over one foot thick, consisting of concrete sandwiched between sheets of steel to make ad-hoc composite armor. For visibility, Killdozer was fitted with three video cameras linked to monitors mounted on the vehicle's dashboard.
A video link, and killdozer and Marvin Heemeyer on wikipedia.