A body found on the Queen's estate was that of a young adult woman and had been at the site for between one and four months, police have said.
Detectives are examining links to cold cases nationwide after the remains were discovered near to the village of Anmer on the Sandringham estate in Norfolk.
They were spotted by a dog walker shortly after 4pm on New Year's Day in woods about a mile from Sandringham House.
A Norfolk Police spokesman said: "The pathologist believes it is highly unlikely the death was through natural causes. Samples have been taken which should provide a DNA profile within the next 24 hours."
Detective Inspector Jes Fry said: "How far back this investigation goes depends on what the experts say. We are looking at missing persons reports nationwide and cases we have been working on more locally for potential links. At this stage we do not know who the victim is."
Mr Fry said police had informed the Sandringham estate and officers responsible for protecting the royals had been updated.