THE latest Fred West probe was sparked after a secret passage was found under a cafe - as cops prepare to excavate six "anomalies" in their hunt for one of his suspected victims.
Evil murderer West was suspected to be behind the disappearance of teenager Mary Bastholm who was last seen near to the site in Southgate Street, Gloucester, more than fifty years ago.
And detectives have since confirmed the possibility that they would be speaking to Rose West while conducting their enquiries.
Officers have been searching the cafe and have identified six potential anomalies in the toilet area 53 years after 15-year-old Mary vanished, the today.
Detective Chief Inspector John Turner, who is leading the investigation for Gloucestershire Police, said a TV production company had identified a void within the floor underneath the toilet in the basement of the cafe.
"They drilled a hole within the void and with the use of a cadaver dog indicated there may be something of interest within the cavity," he said.
"They've then deployed an endoscope and have found an image that looked like blue material within the void.
"The significance of the blue material is that when Mary went missing in 1968, she was wearing a blue dress, a blue coat and a blue bag.
"We have gone over the information provided by the film crew and we've identified six voids within the basement that we are going to excavate."
The work is expected to take about two weeks, with Detective Chief Inspector Turner saying it is expected to reveal "once and for all" if Mary was buried at the site.
The cop also explained that he was “looking for Mary Bastholm” within the cellar, but that he would not confirm that the blue material was linked until they found human remains.
Ground penetrating cameras have also discovered dark blue material matching a coat Mary was wearing when she vanished 53 years ago.
Forensic archaeologists used a ground penetrating radar and discovered a void within the basement of the cafe within two toilet cubicles.
The area was then vented with drill holes, meaning that sniffer dogs were able to access any scent of human remains.
Police dogs indicated a minor to medium reaction, with officers then inserting an endoscope into a hole.
They managed to identify an image which of a blue looking material, which is believe to be Mary’s coat.
Detective Chief Inspector John Turner, senior investigating officer, said: "Fred West was always indicated as being involved in Mary's disappearance and possibly her death.
"We will be searching the basement to find out what, if anything, is there. If anything is found we will carry out a forensic review and we will look to seek people within the investigation that we need to interview.
"If Fred were alive, undoubtedly he would be interviewed around the disappearance of Mary.
I am looking for Mary Bastholm within the cellar
Detective Chief Inspector Turner
"What we are going to do is concentrate on the excavation within the basement.
"As and when we know more, I will then consider whether people need to be interviewed and spoken to and Rose West may be one of those people."
"A member of my team has spoken to Steve West and we will consider all options and line of inquiry once we know exactly what we are dealing with within the basement.”
In September 1967, Fred West and his first wife Catherine "Rena" West moved to a caravan site at Bishops Cleeve, near Cheltenham.
Rosemary West, then a teenager, was living with her parents, Bill and Daisy Letts, in Bishops Cleeve.
Shortly after her 16th birthday in November 1969, Rosemary West moved in with Fred at the caravan site.
Police have said that their "understanding" was that Mary's disappearance in January 1968 happened before Fred had met Rosemary.
Detective Chief Inspector Turner added: "That is my understanding, although there is some suggestion they may have known each other in and around that time.
"The information isn't clear and that is something that would have to be looked at if we were to find anything of significance in the basement."
Gloucestershire police confirmed on today that six "anomalies" in the toilet area are to be excavated.
The major breakthrough comes days after a 39-strong police team led by three archaeologists began analysing the basement of a café in Gloucester, half a mile from West’s home at 25 Cromwell Street.
They are working in an area to the side of the basement which builder West converted into toilets. The material and "suspected bones" are under a partition.
A source said: “Camera images clearly show material which matches the navy blue coat Mary was wearing when abducted.
“In addition, there are images of what look very much like human bones. Great care is being taken to sift through the surface.”
Gloucestershire Police had received possible evidence from a TV production company to suggest the body of the missing teenager could be buried at the location.
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 the meantime, I continue to ask for patience and understanding from all those affected by our ongoing presence at the cafe and thank everyone who has helped us in the last 10 days."
West was a regular at the café, where Mary worked as a waitress before she went missing in January 1968.
He killed himself aged 53 in 1995 while awaiting trial for 12 murders — but admitted he did 20 more.
Mary’s family said in a statement released by police: "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.
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“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.”
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Along with his wife Rose, West tortured, raped and murdered an unknown number of women over a 20-year period.
Mary's body was not found during the 1994 excavation of the West's home, now known as the "House of Horrors", on Cromwell Street in Gloucester.
West's wife Rose, 67, is serving a whole life tariff for ten murders and could be quizzed over any remains that are found.