Gregory J. Haanstad, United States Attorney for the Eastern District of Wisconsin, announced that on February 7, 2025, Senior United States District Judge William C. Griesbach accepted the guilty pleas of Warren J. Grignon. Grignon pleaded guilty to one count of distribution of fentanyl in violation of 21 U.S.C. § 841 and one count of involuntary manslaughter in violation of 18 U.S.C. §§ 1111 and 1153(a).
The indictment and plea agreement revealed that Grignon was an inmate at the Menominee Tribal Detention Center in Keshena on the Menominee Indian Reservation. On December 23, 2024, he distributed fentanyl he smuggled into the jail to three other inmates. All three overdosed; two were revived by additional inmates, corrections staff, and responding officers from the Menominee Tribal Police Department. One inmate could not be revived and was pronounced dead due to a fentanyl overdose.
The sentencing hearing is set for May 16, 2025, at 10:30 a.m., before Judge Griesbach. Grignon faces up to 28 years in prison as well as fines and assessments for each count. He also faces a minimum term of three years and up to a lifetime of supervised release after imprisonment.
The case was investigated by the Menominee Tribal Police Department and FBI with assistance from the Department of Pathology and Laboratory Medicine at the University of Wisconsin School of Medicine and Public Health. Assistant United States Attorney Andrew J. Maier is prosecuting the case in Green Bay’s United States District Court.
