From Brave search:

In June 2004, Marvin Heemeyer, an American welder, used an armored bulldozer to conduct a rampage in Granby, Colorado.01 Heemeyer had feuded with Granby town officials, particularly over fines for violating city health ordinances after he purchased property with no sewage system. Over about 18 months, Heemeyer secretly armored a Komatsu D355A bulldozer with layers of steel and concrete. On June 4, 2004, Heemeyer used the bulldozer to demolish the Granby town hall, the house of a former mayor, and several other buildings. He killed himself after the bulldozer got stuck in the basement of a hardware store he was destroying.2 The incident became known as the "Killdozer rampage." A new documentary called Tread explores the history of the event.0