A woman has been raped by a man who entered her home while an accomplice searched and raided the property.
The two men entered the house in Olney, Buckinghamshire, and one of them sexually assaulted the occupant while the other one searched the rooms.
The pair, who are both white, left the house after stealing an amount of cash, credit cards and jewellery during the attack in the early hours of Saturday.
Detective Constable Kim McHugh, from Milton Keynes CID, said: "We are in the early stages of this investigation and are working to establish exactly what has happened here.
"The victim is in the care of specially trained officers and being fully supported.
"We have officers patrolling the areas and are doing everything to locate these offenders, so please speak to them if you have any concerns.
"If anyone has any information, I urge them to contact us immediately."
Anyone with information is asked to contact Thames Valley Police on the 24-hour police inquiry number 101.