Ryan Holteen, 32, was killed at the Edmonton Institution September 26 only a few weeks after being sentenced for armed robbery and other offences during a home invasion last year in Grande Prairie.
Edmonton police say Holteen, who was from Sylvan Lake, Alta., died of multiple injuries.
Kimani Crawford, who is 20, and 26-year-old Roderick McNeil are each charged with second-degree murder.
Christopher Macoon-Evans, who is 24, and Randy Tuccaro, who is 33, face charges of accessory after the fact to murder and are to appear in court Nov. 6.
No court date has been set for Crawford and McNeil.
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