When fredo arrives in cuba with the 2 million , and meets up with michael in his hotel room fredo asks is there anybody around he knows , Michael names roff and johnny ola then asks fredo if he knows them which fredo denighs . forwarding on to the new years eve party , when michael introdues johnny ola to fredo he says "oh you dont know my brother freddie do you " Was this juat an inocent introduction or did michael smell a rat , as of course if fredo did not know ola , why should ola know fredo .