The U.S. Attorney's Office said Wednesday agents arrested Matthew O'Neill Tuesday and booked the 51-year-old Kremmling man on federal charges, including perpetrating a hoax related to a terrorism offense, The Denver Post reported.
O'Neill, who owes $15,000 in back taxes for 2006 and 2007, allegedly mailed a manila envelope to the state Revenue Department. A staff member working on his tax case said a white powder fell out when the envelope was opened, court documents said. The May 25 incident prompted the evacuation of more than 500 workers from the building.
A hazardous materials team later found the substance to be baking soda.
But if convicted, O'Neill faces up to five years in prison and a $250,000 fine.