Federal Prison Inmates Sentenced for the Death of Fellow Inmate

DENVER – The U.S. Attorney’s Office for the District of Colorado announces that Jonathan Guillory, 45, and Anthony Bell, 44, both federal inmates at the U.S. Penitentiary-Florence, Administrative Maximum Facility (ADX) in Florence, Colorado, were sentenced for their roles in the death of a fellow inmate.

According to the plea agreements, on December 6, 2021, a violent altercation occurred inside a cell at ADX involving Guillory and the victim. During the confrontation, Guillory repeatedly stabbed the victim with a homemade weapon, including a fatal wound to the base of the throat. While the assault unfolded, Bell exited the cell and deliberately held the door shut, preventing the victim from escaping or receiving assistance.

Guillory was sentenced to 88 months for voluntary manslaughter and Bell was sentenced to 27 months for involuntary manslaughter.

“This case underscores our unwavering commitment to safety within the federal prison system,” said United States Attorney Peter McNeilly. “Acts of violence, even behind bars, will be met with serious consequences. These defendants now face significant additional time to reflect on the gravity of their actions and the reach of the law.”

“The FBI does not give felons a free pass to commit crimes because they are already serving federal time,” said FBI Denver Special Agent in Charge Mark Michalek. “Violence behind bars – whether committed against prison staff or fellow inmates – brings consequences, as this case demonstrates.”

United States District Judge Regina M. Rodriguez sentenced Bell on June 12, 2025, and sentenced Guillory on June 18, 2025.

This case was investigated by the Federal Bureau of Investigation. The prosecution was handled by the Violent Crime and Immigration Enforcement Section of the U.S. Attorney’s Office.

Case Number: 1:23-cr-00391-RMR