Agents arrested Richard Sandberg, 35, in his Jefferson County home Thursday, charging him with one count of possession of an unregistered firearm, and seizing a stockpile of arms that included M67 military grenades and pipe bombs, KCNC-TV, Denver, reported.
"These improvised explosive devices have been transported to another location where they will be rendered safe," U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives Special Agent Brad Beyersdorf said.
An arrest affidavit said Sandberg claimed he was a "demolition expert and said the U.S. government paid him hundreds of thousands of dollars to learn how to build bombs and kill people." Investigators said he traded the homemade explosive devices for cocaine.
He also claimed a "right wing Declaration of Independence/Constitutionalist political manifesto," the report said.