DENVER -- A bizarre situation developed in the small mountain town of Granby, Colo., Friday afternoon, when a heavily-armed man knocked down at least six buildings with his homemade armor-plated bulldozer before being stopped.

The massive, heavily modified D-5 Caterpillar was finally stopped around 4:40 p.m. and law enforcement officers were climbing over it, assessing the situation and trying to get inside. It was reported that the driver was killed, but that has not been confirmed.

Jim Hulahan, the emergency manager for the town, said that there has been no contact with the person inside and it is very quiet inside the vehicle. He said officers are trying to find a way to break into the bulldozer, which apparently has been welded shut from the inside with heavy steel and concrete.

"There's no way out or into that vehicle," Hulahan told Denver television station KMGH.

The driver of the bulldozer has been identified as Marvin Heemeyer, a lifelong county resident in his 50s, KMGH reported. He reportedly had several problems with the city over the years, and had owned a muffler repair shop in town, the station said.

"He's a person who had a business here in the county and was put out of business so I think he's just got some vengeance with the town and the people who represent the town," Granby resident Alicia Draper said.

Witnesses say it must have taken Heemeyer at least a couple of months to plan his alleged attack, since the vehicle was so heavily fortified and nearly impenetrable. The machine had large steel plates welded onto it and had areas for the driver to shoot out of, areas that one witness described as "gun turrets."

"It's an ugly beast. It's been sealed up well," Draper said.

The rampage began around 3:15 p.m. when the bulldozer began barrelling through the library and town hall, which are in one building, and also smashing through the two-story Sky-Hi newspaper office, demolishing it.

It ran through a cement plant and Xcel Energy service building, and over at least three police cars that had been put in its path to block it, according to witnesses. The driver also hit the town's fire station and the new Liberty Bank building, heavily damaging it. This is the area where Heemeyer's shop was once located, so that may be a reason they were targeted, Draper said.

The bulldozer driver then headed west out of town, pursued by law enforcement vehicles.

There were reports that Heemeyer was armed with a large-caliber automatic weapon. The local radio station said the weapon used by the man was the size of a .50-caliber machine gun.

Several eyewitnesses told KMGH that the scene in the downtown area was chaotic as numerous law enforcement officers converged on the area, shooting at the bulldozer in an attempt to immobilize it as it carved out its path of destruction through town.

A short time later, the bulldozer turned around and headed back into town, moving down the side of the Gambles Hardware store. The bulldozer became stuck in a rear building behind the hardware store. That's where the Grand County Special Response Team moved in around 4:40 p.m.

The Jefferson County Bomb Squad is also at the scene, in case explosives are found.

At one point, the Grand County Road and Bridge Department moved a large earthmover (pictured, left) into the rear path of the bulldozer, in an effort to block it. A smaller bulldozer was moved into the front path of the larger machine, but that did little to slow down the dozer.

"The piece of equipment is so big it's hard to stop," said Lurlene Curran, the Grand County manager, while the bulldozer was moving down the main street in town. "We're doing everything we can to stop this chaos."

From AirTracker7, the scene looked like a tornado had swept through, with selected buildings damaged and demolished, but it wasn't a natural disaster that had occurred, as evidence by the bulldozer tracks streaking its way through Main Street.

"He has systematically severely damaged the town of Granby," said Curran.

"The hit to downtown Granby is huge. We just embarked on an ambitious downtown redevelopment effort and this will not help," Granby Mayor Ted Wang told KMGH. Wang said the Liberty Savings building that was damaged was just erected within the last year.

Although there was an incredible amount of damage to the small mountain town of 2,200, fortunately, there were no reports of injuries.

Residents in the downtown area received reverse 911 calls and were evacuated from the area or put in lockdown mode as bullets flew between the bulldozer and law enforcement. All of this chaos occurred during a very active part of the day, so some say it is a miracle that not one person was hurt.

To help in the continuing investigation, the Colorado State Patrol closed U.S. Highways 34 and 40 around Granby. The mountain town is located just south of the intersection of the two highways, about 50 miles west of Denver.

Gov. Bill Owens is expected to visit the site sometime Friday night.

Some residents told KMGH that it doesn't shock them that Heemeyer may have gone on a revenge-inspired rampage.

"He seems to be a normal guy; he's just different," Draper said. "I've talked to some people and this is not surprise to see him do this."

Granby Attack Mirrors Previous Incident

The bulldozer attack in Granby is reminiscent of a 1998 heavy equipment attack in the Park County town of Alma.

In that case, a 50-year-old man was accused of shooting and killing the former mayor, firebombing town hall and then driving a stolen front-end loader into a number of buildings, including the post office, fire department and water treatment plant.

The man also burned down his own home and was captured after running into the nearby forest. Thomas Leask was sent to the state mental hospital, where he remains today.