MINNEAPOLIS -- A Houston County man featured in Popular Science magazine as a pyrotechnics expert pleaded guilty Tuesday in U.S. District Court to an explosives charge.

Kenneth Ray Miller, 58, pleaded guilty to a count of manufacturing and dealing explosive materials.

Miller came to the attention of law enforcement after being featured in a Popular Science photo essay ran online in 2019. In the piece, Miller is identified as a pyrotechnics expert who "designs smoke displays for NFL games and air shows, but he tests his most destructive creations at home."

Through that piece that the Bureau of Alcohol, Tobacco, Firearms and Explosives became aware that Miller was manufacturing pyrotechnics on his property in Brownsville,. Due to previous felony convictions, Miller is prohibited from possessing firearms and manufacturing and dealing in explosive material, according to the U.S. Attorney’s Office District of Minnesota.

When law enforcement searched Miller's home and workshop in June 2019, ATF agents found homemade smoker generator devices which had several components including an igniter and smoke composition chemicals. The smoke generator devices found used electric matches as igniters, which are regulated devices found on the ATF's Annual List of Explosives.

Newsletter signup for email alerts

Agents also found three firearms as well as thousands of rounds of ammunition.

ATF agents again searched Miller's property in March 2020 and discovered that he "had acquired additional materials for making his homemade smoke generator devices," the plea agreement states.

"When ATF arrived, three packages containing 90 of these devices were awaiting pickup from FedEx," the document states. "ATF seized the packages, and laboratory testing showed that the smoke generator device contained the regulated chlorate explosive mixture."

He did not have a license, permit, exemption or any other authorization from the ATF to posses or use either of those items.

Agents again found thousands of rounds of ammunition during the March search.

Miller has two previous federal convictions. In 1986, Miller was convicted in Texas for illegally manufacturing explosives. In 1993, he was convicted in North Dakota in for illegally possessing firearms as a felon.

As part of Miller's plea, prosecutors agreed to dismiss three other charges at sentencing -- transporting explosive materials, felon in possession of explosives and felon in possession of firearms. Prosecutors also agreed not to pursue charges against a woman for aiding and abetting.

A sentencing date for Miller has not yet been scheduled. He is being held pending his sentencing.