Solution—Anonymous

Joe Martineau is not the leader, Deadly (a), or (b) the treasurer. Alvin Fonda (b) is neither treasurer nor leader. Ralph Coburn (c) is not the leader, hence the leader, known as Deadly, is Rex Stover. And, as the leader is not the treasurer, we see in (b) that Coburn is the treasurer. Therefore, as neither the leader (Stover), the treasurer (Coburn), nor Fonda (d) is the foreigner, he is Joe Martineau.