Jonathan Guillory and Anthony Bell, both inmates at the U.S. Penitentiary-Florence, Administrative Maximum Facility (ADX) in Colorado, have been sentenced for their involvement in the death of another inmate. The incident took place on December 6, 2021.
According to plea agreements, Guillory engaged in a violent altercation with the victim inside a cell at ADX. During this confrontation, he repeatedly stabbed the victim with a homemade weapon, causing a fatal injury to the throat. Meanwhile, Bell exited the cell and intentionally held the door shut to prevent any assistance from reaching the victim.
Guillory received an 88-month sentence for voluntary manslaughter, while Bell was sentenced to 27 months for involuntary manslaughter.
"This case underscores our unwavering commitment to safety within the federal prison system," stated 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 Guillory on June 18, 2025.
The Federal Bureau of Investigation conducted an investigation into this case which was prosecuted by the Violent Crime and Immigration Enforcement Section of the U.S. Attorney’s Office.
Case Number: 1:23-cr-00391-RMR
