Gloucestershire Police said no other “material of importance” had been discovered at the Clean Plate Cafe, which is on the same site as an old cafe – the Pop-In – where Mary worked as a waitress.
She was last seen alive in January 1968.
The Bastholm family said in a statement: “We are still very sad that Mary has not been found. We hoped to get a final closure on her disappearance so that we could put her to rest. “
They described her as a “strong willed and happy teenager, much loved by her parents and her two brothers”.
Her life was “tragically cut short” when she disappeared and her family “was never the same after her disappearance,” they said.
Gloucestershire Police said in their statement: ‘The search work at the Clean Plate Cafe is now complete and we cannot confirm that no human bodies or items important to the investigation have been found.
“The excavations to access and examine six areas of interest or“ anomalies ”in the cellar began on Wednesday, May 19.
“The anomalies were identified by a team of forensic archeology experts and anthropologists before the excavation work, with the experts having determined that the remaining areas of the cellar had not been disturbed since before 1968, when Mary Bastholm is missing.
“Each area has been carefully examined by the forensic team with the support of the gendarmerie officers.
“The team worked every day, everything that was unearthed was analyzed on site and all activity was meticulously recorded and photographed. “
Police said the cafe would be returned to its owners after the repair work was completed.
The owners of the Nelson Trust said their “support for the police” had “always been driven by what we believed to be in the best interests of the family.”
Deputy Chief Constable Craig Holden said at a press conference Thursday: “Everyone working on this is disappointed that they couldn’t find Mary. “
But he said the investigation was “appropriate and proportionate” and “that doesn’t mean we were wrong to watch.”
Thoughts of the force are with his family “whose dignity has been humiliating,” he added.
Police began investigating the site earlier this month after being alerted to possible evidence of human remains in the cellar by a team of documentaries filming there.
ACC Holden said the “blue material” photographed by the production company was not found, but was likely connected to a buried pipe.
Mary worked at the Pop-In Cafe on Southgate Street before she passed away in 1968 at the age of 15, a time when Builder West was kidnapping girls in Gloucester.
West was suspected of having disappeared but committed suicide in prison, aged 53, in 1995. He allegedly confessed to killing the teenager during a conversation with his son, Stephen, but did not. had never admitted to the police.
Mary’s body has never been found and was not discovered during a search of the House of the Wests – known as the House of Horrors – on Cromwell Street in Gloucester in 1994.
West was charged with 12 murders but committed suicide before his trial.
Rose West, his wife, was convicted of 10 murders in November 1995 and is serving a life sentence.