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?

At 12.20am on 29 June, Paul Griffiths found the battered body of his father. Seconds earlier Paul had seen a man heading towards Cricklewood Broadway: viewers may be able to identify him.

Someone may know the whereabouts of Andrew Elphick, missing since August and feared dead. And long-distance lorry drivers may hold the key to the murder of 42-year-old Vera Anderson.