Pierre Ouellet didn't return to a home in Montreal last week and, according to police, he swiftly obtained a handgun and robbed a pair of Quebec City grocery stores on Thursday and Friday.
Ouellet was sentenced to life in prison for the 1986 slaying of a Montreal police officer, Claude St-Laurent.
He had been pulled over and was able to disarm the constable before shooting him with his own service revolver near Montreal's Olympic Stadium.
A quarter-century behind bars has failed to rehabilitate him, according to police.
Quebec City police said they had surveillance video showing him brandishing a gun at the grocery stores. They called him armed and dangerous.