But did Pentangeli really turn on Mike? Pentangeli was tricked into believing that Mike tried to whack him, so he made a deal with the FBI to rat him out. However when Pentangeli saw his brother sitting with Michael, he immediately realized that his loyalty should have been to Michael, and he basically screwed his own immunity deal by recanting his earlier testimony which would have resulted in Michael going to prison. Then, as the ultimate sacrifice he killed himself with the understanding that his family would be taken care of. I can see that Clemenza would have fallen for the same rouse, but I thought the Pentangeli character was really a plus.