In an open letter published by La Presse newspaper, the police officers called for accountability for the wrongful detention and mistreatment of Afghan farmers and others who "found themselves in the wrong place at the wrong time in the middle of urban warfare."
A military police complaints commission launched an investigation last November into the allegations first raised by an interpreter and Canada's former ambassador to Afghanistan. It is ongoing.
Military police were ordered to "terrorize" the detainees to make them more amenable to interrogation, they said.
Detainees, they said, would be awakened in the middle of the night, visibly "frightened and in a panic" to find up to 50 soldiers in their cell.
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Almost half would turn out to be villagers or farmers with no ties to the Taliban insurgency, and would be released.
But this would come only after being held for up to two months, they said, far longer than the average 48-96 hours of detention claimed by the Canadian government of the day.
"Almost 50 per cent of the prisoners held by military police were just people like you and me, husbands, fathers, farmers, who had nothing to apologize for. Why and how could this contempt for our laws and Canadian values have occured," the policemen said in the letter.
The mass roundups, they concluded, were motivated by a desire to kill or incarcerate the largest possible number of Taliban and bring a swift end to the conflict in which 162 Canadians died and more than 2,000 were wounded.
A spokesperson for the Canadian government was not immediately available for comment.