Forensic archaeologists have been undertaking exploratory work at the Clean Plate cafe in the city’s Southgate Street in connection with the disappearance of Mary Bastholm.
So what do we know so far?
Bastholm was 15-years-old when she disappeared in January 1968. She was last seen alive waiting at a bus stop on Gloucester’s Bristol Road.
She worked at the Clean Plate at the time – the place where West’s first known victim, Anne McFall, was also employed.
The police search of the place came after an ITV documentary team led by Sir Trevor McDonald took a cadaver dog into the building and it reacted positively in the basement.
Producers called in Gloucestershire Police after also finding what appeared to be blue material in one area of the cellar. Bastholm was wearing a blue coat when she went missing.
Forensic archaeologists have since confirmed that there are a number of structural anomalies within the basement that they say warrant further exploration.
Crucially, perhaps, it has long been thought – though never confirmed – that West did renovation work there a month before the teenager’s disappearance.
West murdered at least 12 girls and women over a 20 year period from the late Sixties, the majority with his second wife Rose.
The couple were caught after nine skeletons were found buried in the cellar and garden at their home in at 25 Cromwell Street in 1994. A silver locket believed by Bastholm’s family to have belonged to her was also found.
He killed himself in prison in 1995 just weeks before he was due to stand trial for the killings but, before he did so, he is reported to have admitted to his son Stephen that he also killed Bastholm.
His daughter Mae has said that it was unlikely Rose – an inmate at HMP New Hall, in Flockton, West Yorkshire – knew much about the disappearance.
“I think Mary’s murder was before her time but how do I know what they discussed?” she said. “I probably asked mum about Mary when we were in safe houses. Police said we were the best officers they’d known – we’d question mum about things that they had just told us.
“She never said anything. I don’t know how she would have known, because mum would have been 15 when Mary disappeared. That’s not to say that they didn’t speak about it between them.”
In a statement, Bastholm’s family said: "Senior investigating officer John Turner has sat with us and explained the ongoing investigation as well as his intentions to excavate the cafe to try and find Mary.
"We are extremely happy Gloucestershire Police is continuing to try and search for Mary and this gives us a chance to potentially put her at rest after all these years.
"We want to thank everyone who has wished us support through this distressing time, and we are continuing to be in close touch with the investigation team, and are being kept up to date with any new developments.
"We hope this is a chance to finally get closure for Mary and would like to continue to ask for privacy whilst the excavation is ongoing."