On May 16, 2025, Senior United States District Judge William C. Griesbach sentenced Warren Grignon, a 43-year-old resident of Keshena, Wisconsin, to 12 years in federal prison. The sentence was handed down for Grignon's role in distributing fentanyl within the Menominee Tribal Jail, which resulted in three overdoses and one fatality. This sentencing follows Grignon's guilty pleas on February 7, 2025, to charges of involuntary manslaughter and distribution of controlled substances.
Court records reveal that Grignon was booked into the tribal jail on December 22, 2023. By December 23, he had distributed a substance containing fentanyl to three other inmates. All three inmates ingested the drug and subsequently overdosed. While jail personnel, tribal police, and EMTs were able to revive two of the inmates, one inmate did not survive.
During the sentencing hearing, Judge Griesbach emphasized the gravity of the offense and its significant impact on the community as reasons for imposing a lengthy prison term. In addition to his prison sentence, Grignon will be subject to supervised release for an additional ten years and must pay $6,943 in restitution to the victim’s family.
The investigation was conducted by the Menominee Tribal Police and Federal Bureau of Investigation. Assistant United States Attorney Andrew J. Maier prosecuted the case in Green Bay's United States District Court.