Marvin Heemeyer made international headlines on June 4th 2004, when he, as the result of a zoning dispute, took to a homemade, reinforced, armoured Komatsu D355A bulldozer (which the media has since dubbed the "Killdozer"), and began demolishing buildings in Granby, Colorado, (including both the Town Hall and the house of the former mayor). Ultimately, after his bulldozer became stuck in a building's basement after trying to demolish it, Heemeyer drew a .357-caliber handgun and shot himself in the head.
The zoning dispute began in 2001, when construction was approved for a cement manufacturing plant in a lot near Heemeyer's muffler shop (said particular lot being used frequently by Heemeyer to get to and from his business). He failed multiple times to appeal the decision, and, adding fuel to the fire, was later fined $2500 for having junk cars on his property, and for not having his business connected to the sewer line. In a last ditch effort, he tried petitioning the city, although was unsuccessful. Admitting defeat, he decided to purchase a bulldozer, with the intention of creating an alternative route to his shop, although, this too was rejected by city officials. It is at this point that Heemeyer cracked, and began work on his "Killdozer".
Over the course of one and a half years, Heemeyer reinforced his bulldozer using concrete and steel. In addition to armouring the bulldozer, he also installed mounted rifles and several video cameras (which he linked up to corresponding monitors inside). His two hour rampage took out thirteen buildings in total, starting with the very building that had sparked the whole dispute; the cement factory. Despite efforts from police, none of their weapons were able to penetrate the bulldozer's armour. The final building destroyed was Gambles hardware store, in the basement of which the bulldozer became stuck, as previously mentioned. In total, he caused roughly seven million dollars worth of damage.
Shortly before embarking on his rampage, Heemeyer recorded a series of audio tapes outlining his motives (totalling roughly two and a half hours, the last recording of which was created just thirteen days beforehand) and mailed them to his brother in South Dakota, who in turn handed them over to the FBI. The FBI then turned them over to the Grand County Sheriff's Office, who are said to have released them, although all that can be found of them online today are small segments that seem to have been broadcast during news reports and other TV shows regarding the incident. It is unknown exactly as to the scale of the Grand County Sheriff's Office's said "release" (ie. to whom the recordings were made available, and in what quantities).
UPDATE: The recordings have been found. You can listen to them here.