A southern Minnesota man was illegally building and selling homemade explosive devices from 2013 until last June, according to a federal indictment unsealed Wednesday.

Federal agents arrested Kenneth Ray Miller, 58, of Houston County, this week. Miller appeared in court Wednesday.

The four-count indictment alleges that Miller manufactured, dealt and transported explosive material without the required license or permit. That included a highly combustible chlorate chemical mixture and smoke-generating devices containing electric lighters.

Law enforcement also seized a revolver, shotgun and rifle from Miller, who is not permitted to have guns because of a previous felony.

In 1986, Miller was convicted in a conspiracy to manufacture explosive materials. In 1993, he was arrested for illegal possession of a gun.

The indictment contains no information regarding how much money Miller made off the operation or how the explosives were used.

The arrest followed an investigation by the Bureau of Alcohol, Tobacco, Firearms and Explosives, with help from the Houston County Sheriff's Office, the St. Paul Police Department, the U.S. Environmental Protection Agency, the Minnesota departments of Natural Resources and Public Safety.