Inside The Shocking Revenge Story Of Marvin Heemeyer And His ‘Killdozer’

Published February 8, 2022
Updated November 7, 2023

After his zoning petition was repeatedly dismissed, Marvin Heemeyer decided to modify a bulldozer into a lethal "killdozer" and go on a rampage in Granby, Colorado.


Craig F. Walker/The Denver Post/Getty Images
Authorities examine the killdozer driven by Marvin Heemeyer through Granby, Colorado. June 5, 2004.

When Marvin Heemeyer of Granby, Colorado, reached a dead-end in his fight with the local zoning commission, the logical response would have been to petition them once again and await a future reply from them. After all, Marvin Heemeyer was known to have been a logical man, so it was expected that he would have taken a logical approach.

Instead, Marvin Heemeyer went home, outfitted his Komatsu D355A bulldozer with armored plates, a layer of concrete, and bulletproof plastic, and drove it through the town in a rampage, knocking down 13 buildings and causing $7 million worth of damage with his makeshift “killdozer.”

This is the shocking true story of Marvin Heemeyer’s revenge.

A Battle Against A Zoning Commission

Marvin Heemeyer

Wikimedia CommonsA rare photo of Marvin Heemeyer, the man who built the infamous killdozer.

During the 1990s, Heemeyer owned a small welding shop in town, where he made his living repairing mufflers. He’d purchased the land on which his shop was built in 1992. Over the years, he had agreed to sell the land to a concrete company to build a plant. The negotiations hadn’t been easy, and he’d been having trouble agreeing with the company on a suitable price.

In 2001, the city approved the construction of a concrete plant, zoning the land next to Heemeyer’s for use. Heemeyer was furious, as he’d used the land for the past nine years as a shortcut between his home and his shop.

He petitioned the city to have the property rezoned to prevent the construction of the plant, but he was rejected on multiple occasions.

So, in early 2003, Marvin Heemeyer decided he had had enough. A few years earlier, he had purchased a bulldozer with the intention of using it to create an alternative route to his muffler shop. Now, however, it would serve a new purpose as his weapon of destruction: the killdozer.

How Marvin Heemeyer Unleashed The Killdozer

Marvin Heemeyer's Killdozer

Brian Brainerd/The Denver Post/Getty ImagesA look inside the killdozer constructed by Marvin Heemeyer.

Over the course of about a year and a half, Marvin Heemeyer customized his Komatsu D355A bulldozer for his rampage. He added armored plates, covering most of the cabin, engine, and parts of the tracks. He’d created the armor himself, using a concrete mix poured between sheets of steel.

As the armor covered much of the cabin, a video camera was mounted on the exterior for visibility, covered by three-inch bulletproof plastic. Inside the makeshift cockpit were two monitors on which Heemeyer could observe his destruction. There were also fans and an air conditioner to keep him cool.

Finally, he fashioned three gun ports and outfitted them with a .50 caliber rifle, a .308 semi-automatic, and a .22 long rifle. According to authorities, once he’d sealed himself inside the cockpit, it would have been impossible for him to have gotten out — and they don’t believe he ever wanted to.

When his killdozer was finished, he readied himself for his attack. And on June 4, 2004, he sealed himself inside his cockpit and set out for Granby.

He drove the machine out of his shop through the wall, then plowed through the concrete plant, the town hall, a newspaper office, a former judge’s widow’s home, a hardware store, and other homes. Authorities later realized that every building that had been bulldozed had some connection to Heemeyer and his lengthy battle against the zoning committee.

Though authorities tried to destroy the vehicle multiple times, the killdozer proved resistant to small arms fire and resistant to explosives. Indeed, the rounds fired at the tractor during the rampage had no ill effect.

For two hours and seven minutes, Marvin Heemeyer and his killdozer pummeled through the town, damaging 13 buildings and knocking out gas services to city hall. Such a panic ensued that the governor considered authorizing the National Guard to attack with Apache helicopters and an anti-tank missile. The attacks were in place and, had Heemeyer not wedged himself in the basement of a store, they would have been carried out.

The End Of Marvin Heemeyer’s Killdozer Rampage

Marvin Heemeyer's Rampage

Hyoung Chang/The Denver Post/Getty ImagesA destroyed truck was stuck inside the Mountain Parks Electric building after Marvin Heemeyer’s rampage.

As Marvin Heemeyer attempted to bulldoze Gambles hardware store, he accidentally got the killdozer stuck in the foundation. With the end clearly in sight, Heemeyer killed himself with a gunshot to the head in his cockpit, determined to avoid capture and leave the world on his own terms.

Despite the nearly $7 million in property damage done to the town of Granby, not a single human besides Heemeyer was killed during the rampage. This is largely because a reverse 911 system was used to notify residents of the killdozer so that they could get out of the way in time.

After the dust settled, authorities searched Heemeyer’s home and found notes and audio tapes that outlined his motivations. They also learned that several men who had visited Heemeyer’s shop didn’t seem to notice the killdozer, which encouraged Heemeyer to move forward with his plans.

As for Marvin Heemeyer’s killdozer itself, state officials decided to take it apart and sell it for scrap. They sent the pieces to dozens of scrap yards to stop admirers of Heemeyer from snatching a piece, as it soon became clear that the killdozer was going to be a subject of fascination.

Indeed, in the years after the rampage, Heemeyer became a controversial folk hero in certain circles, with some believing that he was a victim of a town government that didn’t think twice about hurting a local business. On the other hand, some have pointed out that he initially agreed to sell his land — and more crucially, that he could have easily killed innocent people during his attack if they hadn’t gotten out of the way in time.

In the end, Heemeyer left the world believing that God had asked him to undertake his rampage. Perhaps the most revealing note that he left behind was this one: “I was always willing to be reasonable until I had to be unreasonable. Sometimes reasonable men must do unreasonable things.”

After learning about Marvin Heemeyer’s killdozer, check out some of history’s most unmerciful revenge stories. Then, take a look at some real-life vigilante stories of ordinary citizens taking justice into their own hands.

Katie Serena
A former staff writer at All That's Interesting, Katie Serena has also published work in Salon.
Jaclyn Anglis
Jaclyn is the senior managing editor at All That's Interesting. She holds a Master's degree in journalism from the City University of New York and a Bachelor's degree in English writing and history (double major) from DePauw University. She is interested in American history, true crime, modern history, pop culture, and science.