A 28-year-old woman was raped by a man wearing a hooded top in the early hours of Saturday morning.
The victim was walking at the junction of Bierton Road and Stirling Avenue in Aylesbury between 3.30am and 4.30am when she was sexually assaulted by a man who then ran off.
He is white, between 5ft 10ins and 6ft and was wearing a dark blue or black hooded top and possibly a brown jacket.
Speaking on Sunday, investigating officer Det Sgt Simon Johnson said: “This incident was reported to police this morning and we have a team of detectives working to establish the circumstances of what has happened.
“At this time, we would like to hear from anyone who saw or heard anything in the area of Stirling Avenue between 3.30am and 4.30am.
“If you think you have any information which could help our inquiry, please call 101.”
Alternatively, contact Crimestoppers anonymously on 0800 555 111.