Canada's military grilled hundreds of immigrants and refugees who settled in the country at the height of the Cold War for valuable information, says a new study by a historian from the University of Toronto. The Joint Intelligence Bureau, a section of the Defense Department which handled secret information on economic and military matters, set up an interrogation unit in 1953 to debrief newcomers from Hungary, Poland and other countries, the Canadian Press (CP) reported Monday, citing a report by history professor Wesley Wark.