Roberta Sampson

 was a werewolf. She struck up a friendship with Susan Foreman. After the First Doctor told her to stay away from Susan, she underwent a lycanthropic transformation (became a werewolf), and was shot by the First Doctor in the thigh and shoulder with silver bullets, killing her. The Doctor later stood trial for this crime, but was declared not guilty due to the interferences of the Fifth, Third, Eighth, and Second Doctors. (PROSE: The Juror's Story)