Police are excavating the former home of a paedophile couple who knew serial killers Fred and Rose West.
David and Pauline Williams were jailed at Exeter Crown Court in November for a string of sexual offences dating back to the 1980s.
Their catalogue of abuse started in Gloucester, where they met the Wests, and continued when they moved to Devon in the 1990s.
Devon and Cornwall Police confirmed excavation work had started at an address in Bradninch in Cullompton, Devon.
A spokeswoman said: "Following intelligence received, Devon and Cornwall Police are undertaking excavation work at a property on Cullompton Hill, Bradninch, Cullompton, Devon.
"This relates to historic intelligence connected to the address and its former occupants.
"It is expected to take up to four days to complete.
"Specialist officers will be involved in the excavation, which we hope will have as little impact on the local community as possible."
The couple were convicted of 48 individual and joint charges stretching over 15 years following a trial at Exeter Crown Court.
David Williams was jailed for life after being found guilty of offences including 11 counts of indecent assault, 10 counts of rape and two counts of gross indecency with a child.
He was also convicted of three counts of indecency with a child, two counts of cruelty and two cases of aiding and abetting an indecent assault.
Pauline Williams was sentenced to 12 years in prison with four years on extended licence after being found guilty of two counts of aiding and abetting rape, two counts of aiding and abetting an indecent assault and three counts of indecent assault.
Their abuse on victims as young as seven years old was both physical and sexual.
The investigation into the pair, named Operation Abbey, began in July 2013 when a woman disclosed to a mental health professional that she had been raped and sexually abused by David Williams when she was 15.
She then spoke to Detective Constable Debbie Dow, from the force's child abuse investigation unit, and made a complaint against David Williams.
A number of other people then came forward to uncover the abuse they had been subjected to at the hands of Williams and his wife.
The couple denied all allegations against them throughout the investigation and the trial, despite overwhelming evidence against them.
Speaking after the pair were sentenced, DC Dow said: "David and Pauline Williams carried out a string of sickening and callous sexual attacks on children and teenagers without remorse over a 15-year period.
"Their campaign of abuse started in Gloucester and continued when they moved to Devon and lived in Exeter and Tiverton.
"The abuse was both physical and sexual and undertaken by both David and Pauline Williams; one victim was as young as seven years old when this started.
"These victims, both men and woman, had their childhoods stolen by David and Pauline Williams and all have suffered difficulties throughout their adulthood following this abuse as they struggled to live normal lives."
A neighbour, who asked not to be named, told the Press Association that police officers had been at the bungalow since Tuesday.
She said: "It is pretty gruesome, terrible really.
"I think they only lived there for a couple of years at most. An old lady lived there before, she was a church-going lady, she would be turning in her grave if she knew.
"They obviously moved here as a hideaway because it is a villagey place where nobody would know them.
"The man spoke to me once at a bus stop and I saw the lady a few times, but I didn't know them."
She said nobody knew about the horrific crimes the couple committed until it hit the headlines when they were convicted and jailed.
She said: "We found out they were friends of Fred West, they are terrible.
"It is terrible. You don't expect it, do you?
"No-one has lived in the house since they were jailed - it has been empty."