Cold case detectives investigating the discovery of the headless body of a woman more than 40 years ago say the victim may have been a Danish sex worker.
The body of the young woman was found on an isolated heath at Cockley Cley in Norfolk on August 27 1974. She is thought to have been aged between 23 and 35 and tests later established she was probably a mother.
Despite a huge police investigation at the time and more recently, her killer has never been found and officers have so far been unable to establish her identity.
Norfolk Police now say it is possible the victim was a woman known as The Duchess, who was originally from Denmark but lived and worked around the docks in Great Yarmouth.
Detective Chief Inspector Andy Guy said: "One important line of inquiry remains unresolved. As part of our investigations we employed two scientists to study the victim's isotopic make-up.
"This resulted in both experts believing that the victim had spent time in an area defined as central Europe - this would encompass Denmark, Germany, Austria and northern Italy.
"Another interesting feature was her diet appeared to be predominantly fish and shellfish.
"This led us to one report of a woman known as The Duchess, who lived and worked around Yarmouth docks and was thought to be from Denmark.
"She was known to people in the Great Yarmouth area around 1973/74 but one day just disappeared.
"It may be that The Duchess has nothing to do with this inquiry but we would very much like to be able to eliminate her as the victim at Cockley Cley as we have been unable to establish her true identity."
The victim's body was exhumed several years ago. As a result officers now have a full DNA profile which could help identify her through a family member.
Mr Guy added: "It is absolutely possible we could use the DNA recovered to link the woman to a living family member which could provide the breakthrough in the case.
"I believe if we identify the victim we can identify her murderer."
The woman, dressed only in a pink 1969 Marks & Spencer night-dress, was 5ft 2in.
Her body was found in a cover marked with the logo of National Cash Registers which was later found to be quite rare. The rope used to tie her up was mainly used in agriculture.