A man has been arrested on suspicion of murder after the body of a woman was been found at a National Trust estate.
The man is also being treated for serious injuries, police have said.
They are linking the murder to reports of a man seen acting suspiciously by a pub a few hours earlier.
The victim is believed to be in her 60s, police added.
Officers are appealing for anyone who saw a man behaving strangely near the Fox and Hounds pub in the Christmas Common area of Oxfordshire at around 3.30pm to get in touch.
Anyone who saw anything suspicious in the Watlington Hill area at around 5.50pm is also asked to contact the force.
Senior Investigating Officer Detective Superintendent Craig Kirby of the Major Crime Unit, said: “We have tonight launched a murder investigation following the discovery of a woman’s body in woodland earlier this evening.
“My thoughts remain with the deceased woman’s family at what must be a hugely distressing time.
“We are carrying out a thorough investigation to piece together what has happened to lead to this woman’s death.”
The arrested man remains in hospital where he is being treated and anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555111.