Wisconsin inmate pleads guilty to smuggling fentanyl into detention center causing 3 overdoses, 1 death

(WFRV) – An inmate at the Menominee Tribal Detention Center has pleaded guilty to serious drug charges related to an overdose death.

According to a press release from the Eastern District of Wisconsin Attorney’s Office, Warren J. Grignon, an inmate at the Menominee Tribal Detention Center in Keshena on the Menominee Indian Reservation, has pleaded guilty to charges related to fentanyl distribution and involuntary manslaughter.

In a court hearing on February 7, Judge William C. Griesbach accepted the inmate Grignon’s guilty pleas, which now put him facing a lengthy prison sentence. The Attorney’s Office reports that back on December 23, 2024, Grignon smuggled fentanyl into the detention center and distributed it to three other inmates.

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All three inmates overdosed but with quick action from other inmates, corrections staff, and the Menominee Tribal Police Department, two of the inmates were revived. One inmate could not be saved and died from a fentanyl overdose.

Grignon’s sentencing is set for May 16, 2025, and he could face up to 28 years behind bars, plus fines. The Attorney’s Office reports he also faces a minimum term of three years and possibly a lifetime of supervised release after serving his time.

This investigation was carried out by the Menominee Tribal Police Department and the FBI, with support from the University of Wisconsin. Attorney Andrew J. Maier is prosecuting the case in the U.S. District Court in Green Bay.