Police investigating the death of a former teacher in a road crash want to speak to a elderly couple who stopped at the scene.

Christine Diacon was killed on the A40 slip road near High Cogges, Witney, at about 4pm on Thursday, November 15, after being hit by black Honda.

Now police want to speak to man and a woman, both in their 70s, who were first on the scene but left before police arrived.

The couple were in a car towing a caravan and parked in the lay-be near where the crash happened.

Police are also trying to track the driver of a vehicle which was in front of the Honda before the crash.

This vehicle is described as being a light-coloured, high-backed vehicle and possibly a people carrier, a 4x4 or a van.

Sgt Kerry Clarke, of Abingdon Roads Policing, said: "This driver may not have actually scene the collision take place because it was behind them, but it is vital we speak to them to at least eliminate them from our enquiries.

"However, they could have easily seen the collision in their mirrors or may be able to help us with details of what happened just before the crash.

"The couple in the caravan definitely saw the incident and it is very important we speak to them."

The driver of the Honda was arrested on suspicion of causing death by dangerous driving and released on police bail until 8 January, 2008.

Ms Diacon, in her late 50s, of South Leigh Road, High Cogges, was a former teacher at Henry Box School in Witney.

Anyone who witnessed the crash should contact Sgt Clarke via 08458 505505 or speak anonymously to Crimestoppers on 0800 555111.