S1, E5: The dead body in the park is another victim of the assailant, the first to be murdered. The Chief Superintendent - dissatisfied with Burns progress - seconds Sergeant Fenton to the C.I.D. and take charge of the investigation. Under pressure from Chief Inspector Nelson, Fenton decides to use Dawson as a decoy to flush out the assailant which she readily agrees to despite Burns objections. The plan works and Fenton arrests a suspect and in the confusion Dawson is left behind at the mercy of the real assailant and goes missing. Burns detective work and Fenton's doggedness lead a two pronged search for Dawson that takes the case in a full circle.