GRANBY, Colo. – Friends said Marvin Heemeyer hadn’t been seen much lately, and now they know why: He was turning a bulldozer into an armor-plated vehicle that was impervious to SWAT team bullets.

Friday, the muffler shop owner drove his contraption through town, and within two hours had knocked down or damaged nine buildings before the machine ground to a halt in the wreckage of a warehouse. He then apparently shot himself, said Grand County Sheriff Rod Johnson. No one else was injured.

City officials said he was angry over a zoning dispute and fines for city code violations at his business in the town about 50 miles west of Denver.

Saturday, crews used a crane to remove Heemeyer’s body from the improvised tank.

A friend, Pete Mitchell, said Heemeyer was probably smiling when the vehicle, equipped with a TV camera for guidance, busted out of the side of a garage.

“That’s the kind of guy he was,” Mitchell said, calling his friend “vindictive.”

Heemeyer loved to weld, and this surely was his masterpiece, probably constructed over a period of several months, he said.

Town manager Tom Hale said Heemeyer was angry after losing a zoning dispute over land near his muffler shop. Heemeyer also had been fined $2,500 in a separate case for not having a septic tank and other city code violations at his business, Hale said.

When he paid the fine, he enclosed a note with his check saying “Cowards,” Hale said.

Heemeyer’s first target was a shop at the cement plant about 100 yards from where he built the armor-plated bulldozer. He also damaged a newspaper office, a town hall-library, a bank, a hardware store and a utility office.

Nothing had seemed out of the ordinary at his corrugated-metal building, where he kept cars, snowmobiles, boats and, now it seems, a bulldozer. Mitchell said Heemeyer hadn’t been seen much of late.

His skills as a welder were legendary, Mitchell said.

“He could change a muffler by himself in 20 minutes,” Mitchell said. “No wasted motion. He knew what he was doing.”

Investigators believe he spent several months planning and building the steel box that no police bullet could penetrate. Described by some witnesses as resembling a large trash bin, up close police could see the details of Heemeyer’s handiwork. He had installed TV cameras connected to three monitors so he could see where he was going.

“How he built this was amazing,” said Grand County Commissioner James Newberry. “This was a very intelligent man.”

After blasting the box three times, police found hinges that allowed them to pull out an air conditioning unit and get into the box. Crews had to use a crane to remove Heemeyer’s body. Police initially believed he had welded the box shut from the inside.

Once inside, investigators found four weapons – a .50 caliber rifle, two military style assault rifles and a handgun.

The time of death was under investigation. Officers heard a shot fired from inside the box around 4 p.m. Friday. His death was confirmed early Saturday, and the body removed later Saturday.