Forensic archaeologists have confirmed there are a number of “structural anomalies” in the cellar of the cafe they are searching for evidence linked to serial killer Fred West and a historical missing person case.
Police have been searching the Clean Plate cafe in Gloucester in connection with the disappearance of Mary Bastholm who vanished in 1968 aged just 15.
Serial killer West who took his own life in prison in 1995 aged 53, was previously suspected over her disappearance.
Ms Bastholm’s body has never been found.
The detective leading the investigation says excavation work will now take place following “assessments at the scene, to establish if any human remains are present”.
Gloucestershire Police had received possible evidence from a TV production company who had been making a documentary, to suggest the body of the missing teenager could be buried at the location.
This included an image of what appeared to be blue material buried in one area of the cellar. Mary was wearing a blue coat when she went missing.
Detective Chief Inspector John Turner said: “The analysis from our experts and the material provided by the production company means there is enough evidence to justify excavation work beginning.
“I’ve spoken to the family and was so impressed by their quiet dignity and gratitude for all the work we’ve done and will be doing.
“They understand it is possible we won’t find human remains but they also know that we will do everything we can to establish if Mary is buried at this location.
“This will be slow and painstaking work but we have the best people on it and I can reassure our communities that all involved, from my team of investigators, our scenes of crime officers, search officers and family liaison officers to the forensic archaeologists who will continue their work are absolutely committed to the job ahead.”
In a statement, the teenager’s family said they were happy the police were “continuing the search for Mary” as it “gives us a chance to potentially put her at rest after all these years”.
It added: “We hope this is a chance to finally get closure for Mary.”
Along with his wife Rose, serial killer West tortured, raped and murdered an unknown number of women over a 20-year period.
Mary’s disappearance in 1968 was at a time when West, who often did jobs in the street where she worked as a waitress in a cafe, was abducting girls in Gloucester.
He is said to have confessed to killing Mary in conversation with his son, Stephen, but never admitted it to police.
Mary’s body was not found during the 1994 excavation of the Wests’ home, now known as the “House of Horrors”, on Cromwell Street in Gloucester.
West was charged with 12 murders, but took his own life in a Birmingham prison before his trial.
Rose West was convicted of 10 murders in November 1995 and is serving life.
Officers are expected to be at the cafe for several weeks, the force said.