An elderly man who spoke to a woman before she was raped in an Oxfordshire village is being sought by police.
The 50-year-old woman was attacked by a man and threatened with a knife as she crossed a sports field off the High Street in Eynsham on Sunday night.
He forced her to perform a sex act on him before she pushed him away and ran.
Detectives think the elderly man, who was walking his terrier dog with a young child, may have seen something which could help the investigation.
The attacker is described as about 6ft tall, aged between 20 and 25 and thin.
He had dark hair which was brushed back behind his ears and hung down to his collarbone area.
The man was wearing a white hooded top and dark jeans.
Det Insp Kevin McGuire said: "Prior to the attack the victim had a short conversation with an elderly man who was walking a terrier dog in the area and was accompanied by a young child.
"I would particularly like to speak to this gentleman as he may have information which could assist the investigation."