Petherbridge
From Tardis Wiki, the free Doctor Who reference
Petherbridge was a university researcher at St Ursula's College in 1939. She mistook Peri Brown for Sarah Perry, her favourite writer. She told Peri and the Sixth Doctor about the poison pen letters to Ruth Horwitz. She didn't want the police to look into the matter. She was the principal of the college. (AUDIO: An Eye For Murder)
