She was portrayed by Clare Wille.
Karen had bought Agatha's cottage in Carsely as Agatha was due to move in with her soon to be husband, James Lacey. However, when their wedding was interrupted and Agatha could subsequently no longer live with James, she asked Karen if she was maybe regretting the move to Carsely. Unfortunately for Agatha, Karen was happy in the village and had no intention of selling the cottage back to Agatha.
When taking her dog for a walk, Karen witnessed Agatha be approached by a drunken Jimmy Raisin. Being harassed by Jimmy, Agatha had to whack him out of her way so she could escape the situation. Jimmy fell down the hill and Agatha left him, unaware that Karen had been watching from afar. In fact, Karen recognised Jimmy and became worried that he would start demanding money from her again. With Agatha now gone, Karen went after Jimmy at the bottom of the hill and strangled him to death. She then contacted the police, reporting the violent exchange she had just seen between Agatha and Jimmy. (The Murderous Marriage)
Season 1 (1/8)