On June 4th, 2004, a man named Marvin Heemeyer drove an armored bulldozer through the town of Granby during a rampage that lasted 2 hours. After causing an estimated $7 million worth of damage, Heemeyer killed himself. He was the only casualty of the event. A bizarre story with a sad ending, a documentary was recently released about the incident, produced by Doug Liman and Great Point Media. It’s titled “Tread” and currently has a 7.3/10 on IMDB with an award nomination at the SXSW Film Festival.

Here’s a little bit about what led to this shop-owner hitting a breaking point that caused him to build an armored construction vehicle, thus resulting in one of Grand County, Colorado’s darkest days?

Marvin Heemeyer owned a muffler repair shop and lived in Grand Lake – a town roughly 15 miles from Granby, Colorado. While he was said to have no relatives in the area, he had been a local for more than 10 years prior to his attack.

The motive of the attack can be traced back to happenings of 1992, during which an ongoing zoning battle between Heemeyer and the city was sparked. Heemeyer purchased a small plot of land from a federal agency, with the intention of building his muffler shop on part of it before selling the rest to a company seeking to build a concrete batch plant. Zoning issues prevented the construction of such a plant, and Heemeyer continued to raise the proposed selling price of the partial plot over time. Eventually, the zoning commission approved the construction of the plant in 2001. When this happened, Heemeyer tried to block the approval, as the terms of the initial sale now interfered with his muffler shop operations – the path to his shop would be blocked. That’s when Heemeyer bought a bulldozer – to make a new path to his store – but, the town denied his request to build. He then decided to use the bulldozer for something else.

During the two years between the bulldozer purchase and Heemeyer’s attack, Heemeyer spent countless hours modifying the machine. He installed armor plating on much of the Lomatsu D335A bulldozer, most of which was at least a foot thick and filled with concrete mix. His efforts would eventually allow the bulldozer to withstand three explosives and 200 rounds of ammunition.

The armor wasn’t the only modification he made. He also installed cameras protected with ballistic plastic that would allow him to monitor his surroundings while operating the machine. Several gun ports were also added to the bulldozer, which would allow Heemeyer to fire outwards from within.

On the day of his attack, Heemeyer started off by plowing through several buildings, including his former business and the concrete plant. He also targeted the Town Hall and a local newspaper, as well as buildings representative of others with whom he held a grudge. Over the course of slightly more than two hours, he had damaged 13 buildings in total. No one was killed except for Heemeyer during the event.

Throughout the two hour period, Heemeyer also fired shots at transformers, propane tanks, several officers, and a citizen that tried to use his own heavy construction equipment to derail the assault. Due to the modifications, it seemed impossible to slow Heemeyer down. Attack helicopters are rumored to have been considered, as well as the use of anti-tank missiles, though this was later denied by then-govenor Bill Owens.

Eventually, the assault ended when Heemeyer turned his attention toward a hardware store. By this point, his engine and radiator had taken damage. One of the bulldozer tracks quickly got stuck in the basement of the building, making it impossible for him to move. Shortly after the bulldozer became immobile, SWAT members heard a single shot ring out from inside the cab of the armored vehicle.

More than a decade later, this day continues to loom over the town of Granby. A tragic event unlike any other, Heemeyer’s actions shot Granby to the national spotlight. By the time all was said and done, Heemeyer’s actions caused an estimated $7 million in damages.

In days following the attack, Heemeyer’s brother received tapes in the mail from his late-sibling, thought to be sent just before the rampage started. The tapes indicated that Heemeyer felt as if the assault was his purpose, captured in the line: “God built me for this job.”

Check out Tread if you’re interested in learning more about this subject or hunt down a book written by Patrick F. Brower, the editor at the time of the local newspaper, Sky-Hi News.


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