One of soap’s biggest murder mysteries turned into a tantalising whodunnit? Tonight, as Coronation Street’s evil Theo Silverton was found dead. Since February, when a ‘flash forward’ episode saw Betsy Swain telling detectives she’d found a body on the way home from her mum Lisa and Carla Connor’s wedding party , fans have been on tenterhooks, wondering who was murdered. Now the big question is who did it? James Cartwright, who has played Theo for 18 months, says: “Who has killed Theo? Even