Police in Gloucester, England are searching a café for a body which may belong to a victim of serial killer Fred West.
Fifteen-year-old Mary Bastholm has never been found after going missing on January 6, 1968.
She worked at the café where West was a regular customer.
The BBC reports police were called to The Clean Plate by filmmakers working on a documentary.
They said they had found evidence a body could be buried within the property.
Police could be at the site "for a number of weeks", with excavation work yet to begin, the BBC said.
"This could be a significant development on a case which has gained a lot of public interest over the years," Assistant Chief Constable Craig Holden said.
"On the basis of the information provided to us, we consider this to be new and potentially important evidence in the case of Mary Bastholm, however further detailed assessments will take place over the following few days to determine the extent of excavation needed."
"First and foremost our thoughts are with Mary's family and we would ask that their privacy is respected at this difficult time," he said.
In a statement released via the force, Bastholm's family said: "We are aware of the ongoing developments around Mary's disappearance and are being kept up to date and supported by Gloucestershire Police family liaison officers.
"At this time please may we ask for privacy so we can grieve for Mary."
The café, run by women's charity The Nelson Trust, said it was an "extraordinary twist of fate" the building associated with Wests victims, was part of a charity working to support women at risk from domestic violence.
The murders West and his wife, Rosemary, carried out came to light after he admitted in 1994 to killing their daughter Heather years earlier.
His confession came as police began to search their address - 25 Cromwell St - over her disappearance.
Police found the bodies of nine girls and young women at the house.
He and his wife Rose were jointly charged with nine murders. West was charged with a further three.
He took his own life while awaiting the murder trial the following year.