The monthly programme which attempts to solve crimes with the help of viewers is back after a summer break.

Twenty-four hours after vanishing from her home in Leeds, teenager Julie Dart wrote a letter to say she had been kidnapped. Ten days later her body was found 90 miles away in Lincolnshire. But from clues left behind by her killer police have now compiled a psychological profile of the man they hope viewers will recognise.

Businesswoman Penny Bell was murdered in broad daylight in the car park of a west London swimming pool. Did anyone see the smartly dressed man leaving her Jaguar car?