06/04/2026
Happy Marvin Heemeyer Day!
LONG LIVE KILLDOZER!
On June 4, 2004, Marvin Heemeyer, a disgruntled muffler shop owner in Granby, Colorado, went on a two-hour rampage in a homemade, heavily armored Komatsu bulldozer. Dubbed the "Killdozer", he tore through 13 buildings in retaliation against city officials and neighbors he blamed for a zoning and property dispute.
The Build
Over 18 months, Heemeyer secretly converted a 60-ton Komatsu D355A bulldozer into an impenetrable fortress. The cabin was enclosed in custom steel and concrete composite armor. He had no windows, relying instead on multiple external cameras protected by bulletproof plastic and video monitors inside the cab.
The Grievance
Heemeyer's rage stemmed from a years-long dispute:
Zoning: A local concrete plant was built on a neighboring plot of land, and Heemeyer's repeated appeals and lawsuits to stop it were dismissed.
Fines: He was also heavily fined by the city for not being connected to the local sewage network (he illegally dumped waste) and was penalized over a faulty septic tank.
The Rampage & Aftermath
On the day of the incident, Heemeyer crashed through the walls of his own warehouse and targeted buildings owned by the concrete company, the local newspaper, city hall, and former town officials.
Law enforcement fired over 200 rounds and even brought in a front-end loader to stop him, but the dozer was completely immune to gunfire and physical ramming.
The rampage ended when the dozer’s radiator was destroyed and it fell into the basement of a local hardware store.
Trapped and realizing his escape was impossible, Heemeyer took his own life. He caused over a million in damages but did not kill anyone else.
Before his rampage, Heemeyer recorded audio tapes and wrote notes expressing his grievances, which circulated widely after his death.
