Police are continuing to excavate 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 against children dating back to the 1980s.
Their catalogue of abuse against girls and boys as young as seven started in Gloucester, where they met the Wests, and continued when they moved to Devon in the 1990s.
Devon and Cornwall Police said excavation work had started in the rear garden of the couple's end-of-terrace bungalow in Bradninch in Cullompton, Devon, following a tip-off, and will probably continue for two days.
But the force repeatedly refused to comment on what officers are searching for, with some reports suggesting they are looking for a baby's body.
Speaking at the site, Detective Superintendent Keith Perkin said: "These are ongoing investigations linked to historic intelligence at the bungalow.
"We have specialist search officers involved in the excavation and hope impact on the community is reduced as much as possible.
"In the meantime, we will have extra officers patrolling the area to help offer reassurance to the local community."
Mr Perkin said the work is expected to continue until Friday at the earliest.
The couple were convicted of 48 individual and joint charges stretching over a 15-year-period, following a trial at Exeter Crown Court in October.
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.
An 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 Devon and Cornwall Police's child abuse investigation unit, and made a complaint against him.
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.
Speaking after the pair were sentenced, Ms 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."
She said the couple had "stolen" the childhoods of their victims, both now men and women, who had all suffered difficulties throughout their adulthood following the abuse.
Neighbours described the couple as "eerie" and said they failed to integrate in the close-knit town, which has just one shop.
One, who asked not to be named, said police officers had been at the council-owned bungalow since Tuesday.
"It is pretty gruesome, terrible really," she said.
"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."
She said residents were unaware of the horrific crimes the couple committed until their convictions and prison sentences were reported in local papers.
Two police vans were situated outside the property, 2 Cullompton Hill, with 12 police officers seen entering and leaving through a white wooden garden gate.
A white tarpaulin erected over the back of the house hid the rear garden as the excavation, which does not involve mechanical tools, took place.
The sound of scraping and digging in the garden could clearly be heard from the front of the property, situated behind a busy bus stop.
Residents said they were surprised the couple had been allowed to return to the property while they were awaiting sentence, following their convictions.
A mother, who would only give her name as Suzanne, said: "It was very eerie the fact that they didn't speak to anyone and they just came across as strange.
"They were very solemn, they didn't smile, they didn't make eye contact. We tolerated them once it came out what was going on.
"We just need to move on now. The police have done everything they can to help. Hopefully they will find nothing.
"It would just be unthinkable if they do find anything, it would be awful."
She described Bradninch as "a beautiful village in the heart of Devon".