A Roundup man was sentenced on July 29 to 11 years and eight months in prison, followed by five years of supervised release, for bringing large amounts of methamphetamine from Washington into Montana. Acting U.S. Attorney Mark Steger Smith said William Thomas Duncan, 45, pleaded guilty in March 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 over the case. The government said in court documents that Duncan and a partner regularly traveled to Washington to obtain methamphetamine and returned to Montana to sell it.
Law enforcement began investigating the operation in October 2025 while looking into Duncan’s partner, Jeffrey Frederic Nelson. Nelson pleaded guilty in March 2026 and is scheduled for sentencing in October. An undercover agent purchased multiple pounds of methamphetamine from Nelson in January 2026, which led agents to discover Duncan’s phone number on Nelson’s device.
Agents monitored the two numbers and observed regular trips between Montana and Washington for resupplying drugs. On Jan. 22, 2026, officers executed a search warrant at Duncan’s residence in Roundup, where they found two pounds of methamphetamine, several phones, and more than thirty guns. During an interview with law enforcement, Duncan admitted he trafficked methamphetamine and kept firearms for protection.
Assistant U.S. Attorney Thomas Godfrey prosecuted the case with investigations conducted by the Montana Division of Criminal Investigation and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Project Safe Neighborhoods (PSN), described as “the Department of Justice’s nationwide initiative that brings federal, state, local, and tribal law enforcement… together to coordinate efforts to combat violent crime,” played a role as part of Operation Take Back America.
The U.S. Attorney for the District of Montana focuses on protecting citizens through ethical enforcement of federal laws across its offices located in Billings, Great Falls, Helena and Missoula; it operates under appointment by the Attorney General as part of the Department of Justice, according to its official website.