Throughout the 11-year hunt for Ann Heron's killer, detectives have remained convinced that one man may hold the key to the mystery.

At about 5pm on a sunny August 3, 1990 - the approximate time pathologists believe Mrs Heron died - a blue car was seen speeding out of the drive of her home, Aeolian House, at Morton Palms, on the outskirts of Darlington.

As it turned on to the A67, it almost caused a collision with another vehicle and the people in the vehicle were able to briefly describe its sun-tanned driver, who was aged between 35 and 40.

Another man has also never been traced. He was a male jogger, spotted in a blue singlet vest and black tracksuit bottoms, who was running along the A67 near the Heron's house.