S4·E3 Electric Vendetta

A man's naked body is found in a crop circle, then another dead man electrocuted at the wheel of his vehicle, and then yet another dead man in another crop circle. Barnaby is not impressed by rumours of extra-terrestrial killings, and is sure he is dealing with a human murderer. Before he can solve the mystery, he has to fathom a forty-year-old rivalry in love, the vengeance of the loser, and the defences of the winner.