A retired Canadian police officer serving as a UN peacekeeper in Haiti was shot to death Tuesday in an ambush near a slum on the outskirts of the capital, the United Nations said. Mark Bourque, from Stoneham, Quebec, was ambushed with another peacekeeper as they drove near the volatile Cite Soleil, said UN spokesman Marc Jaquet. He was seriously wounded in the leg, and later died from the injuries. Bourque, 57, was among a group of about 25 retired Canadian police officers who had come to Haiti to help organize and monitor the January 8 national elections. "Deceased in an ambush, Mr. Bourque was in Haiti because of Canada's efforts to promote good governance and democracy. His work there was the expression of the most noble of Canadian values," Canadian Prime Minister Paul Martin said in a statement. The UN has begun an investigation into Bourque's death. It appeared Bourque had been wearing a UN uniform but was driving an unmarked car, UN spokesman David Wimhurst said.