Last in the series tonight, and as the title of the show implies, this programme is really not for the faint hearted. Tonight Professor David Wilson investigates Robert Black, who is currently serving life in prison for the killings of four children in the 1980s. He looks into Black's past revealing a shocking history of abuse and repeat offences that went unchecked. He listens to disturbing taped interviews the criminal gave where he reveals just how dark his mind is, leading Professor Wilson to believe he was responsible for many more crimes than he was convicted for.