BILLINGS - A Roundup man who was bringing large amounts of meth from Washington into Montana was sentenced today to 11 years and eight months in prison, followed by five years of supervised release, Acting U.S. Attorney Mark Steger Smith said.

William Thomas Duncan, 45, pleaded guilty in March 2026 to one count of possession with intent to distribute methamphetamine and one count of possession of a firearm in furtherance of a drug trafficking crime.

U.S. District Judge William W. Mercer presided.

The government alleged in court documents that Duncan and a partner regularly traveled to Washington to pick up methamphetamine, bringing it back to Montana to sell.

Law enforcement first learned of the trafficking activity in October 2025 while agents were investigating Duncan's partner, Jeffrey Frederic Nelson. Nelson pleaded guilty in March 2026 to distribution charges and will be sentenced in October. An undercover agent bought multiple pounds of methamphetamine from Nelson in January 2026 and, following a search, discovered Duncan's number on Nelson's phone.

Agents surveilled the two numbers and discovered the pair making regular trips to Washington to resupply their stash of methamphetamine. The undercover agent again arranged to buy methamphetamine from the two men. And then on Jan. 22, 2026, they served a search warrant on Duncan's residence in Roundup, where they discovered 2 pounds of methamphetamine, several phones and over 30 guns. In an interview with law enforcement, Duncan admitted to trafficking the methamphetamine and said the firearms were for his protection.

Assistant U.S. Attorney Thomas Godfrey prosecuted the case. The Montana Division of Criminal Investigation and the ATF conducted the investigation.

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