Unknown to everyone except Dorothea, her son Leonard was a serial killer who, in 1990 raped and then murdered three young girls by strangling them with a striped necktie in Ravens Wood. When Dorothea learned of this, she was unable to turn her own son over to the police and instead she forbid him from continuing with killing.
Nine years later, the body of Carla Constanza was found in Ravens Wood with a necktie wrapped around her neck. Although Leonard was innocent of the murder, Dorothea mistakenly thought that he had become active again, and to prevent him from hurting anyone else, she slashed him to death while he took a bath. She was taken to the hospital, where she confessed all to DCI Barnaby.