A woman was raped by a man who grabbed her in an underpass in the early hours.
Police said the attack was under Silbury Boulevard in Milton Keynes between 03:15 and 03:30 BST.
The attacker grabbed the woman, aged in her 30s, from behind, said the Thames Valley Force.
The man is described as white with ginger hair and beard. He was wearing a dark-coloured bobble hat, a black coat, black jeans, and black wellington boots.
Police are appealing for witnesses and for anyone with dash-cam footage from the area at the time to come forward.