The RCMP said Tuesday the 23-year-old man was found unconscious at Stony Mountain Institution Monday and later died.
The correctional service says Tommy Beaulieu was serving a sentence of just under 10 and-a-half years after being found guilty of aggravated assault of a peace officer and robbery with violence.
He was convicted for his role in a string of crimes that led to the shooting of Corporal Graeme Kingdon in Onanole, Man., in August 2018.
Kingdon survived the shooting but was left with severe injuries after being shot in the head.
Beaulieu was about eight months into his sentence at the time of his death.
The CSC says it is continuing to investigate, and no cause of death has been released.
–With files from Will Reimer
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