Ragan Crezzen

 was used in one of Dr Sa Yy Findecker's experiments, and sent him back in time. He wanted to kill Findecker because of what he did to Sasha Dialfa. He showed Tegan that Nyssa was to marry Magnus Greel. He managed to capture the Fifth Doctor from Findecker. He tried to arrest Greel, he was aged before his time by the Zigma energy. (AUDIO: The Butcher of Brisbane)