A MAN captured on camera just minutes before a sexual assault may hold the key to finding the attacker, police said tonight.

Officers released CCTV footage of a man seen crossing High Street, Wallingford, just 20 minutes before the serious assault.

The footage then shows the man walk over Wallingford Bridge towards where the attack happened.

A 21-year-old woman was sexually assaulted in an alleyway beside the recreation ground in Crowmarsh Gifford at about 2am on December 30.

Det Sgt Darren Cartwright, of South Oxfordshire CID, said: "This man may be a very important witness, then again he may have nothing to do with it, but it is vital we eliminate him from our inquiries."

No one has yet been arrested in connection with the attack.

Anyone with information should call police on 08458 505505.