British police investigating the case of three women held captive at a south London house for 30 years say they have uncovered a complicated and disturbing picture of emotional control.
The women, aged 69, 57 and 30, were rescued in Lambeth last month but news of their plight did not emerge until this week, the BBC reports.
Commander Steve Rodhouse told a press briefing that the three women told police they had been beaten.
It has emerged the couple suspected of keeping them as slaves, both aged 67 and understood to be married, were arrested in the 1970s, but police are not revealing the reason.
On Thursday, police revealed the women, a 69-year-old Malaysian, a 57-year-old Irish national and a 30-year-old Briton, had managed to leave a house in Lambeth on 25 October.
Mr Rodhouse described the three women as having been restrained by "invisible handcuffs" and confirmed they have made a clear allegation of slavery against the two suspects, who have also been arrested on suspicion of immigration offences. It is not believed the women are victims of trafficking.
"What we have uncovered so far is a complicated and disturbing picture of emotional control over many years, brainwashing would be the most simplest term, yet that belittles the years of emotional abuse these victims have had to endure.
Mr Rodhouse said it was "not as brutally obvious as women being physically restrained inside an address and not allowed to leave."
The rescue was staged after the 57-year-old secretly gained access to a phone and contacted Freedom Charity. Following a number of conversations over a week, the women left the property when the occupants of the house were not around.
It is not yet known if the women are related but police believe the 30-year-old has spent her whole life in captivity. Officers are trying to establish whether she was born in the property.