How about killing in ROTJ while he is still frozen in carbonite?
Leia (disguised as Boushh) approaches ‘Carbo-Han’, but just before she is able to initiate the thawing process … someone shots Han right from behind in the heart. Leia turns around … and there is Boba Fett. Of course Leia whould have to kill Boba Fett during the Sarlacc battle.