Officers said there may have been “many and varied offences” against the women, but their ordeal may not be defined as modern-day slavery.
The Metropolitan Police confirmed that interviews were ongoing yesterday afternoon.
According to reports, the women are Josephine Herivel, 57, from Ireland; Rosie Davies, 30, from England; and Siti Aishah Abdul Wahab, 69, from Malaysia. The names have not been confirmed by police.
Last night, Hasnah Abdul Wahab, of Negeri Sembilan, outside Kuala Lumpur, was planning on flying to London, with an old portrait of her younger sister, in the hope of being reunited with her.
Police agreed to wait until last week to arrest the suspected captors, said to be Maoist activists Aravindan Balakrishnan and his wife, Chanda Pattni.
Police have had indirect contact with the three alleged victims, whom it is claimed were “brainwashed” into remaining in a political collective for more than three decades.
Commander Steve Rodhouse said: “The victims are in the care of specialists who have got great experience of dealing with people who have been subject to trauma.
“We’re working to the advice of those experts as to how best to handle those victims, to support them and, of course, to draw out the evidence we would need to substantiate any prosecution.”
He added: “We need to maintain an open mind on what this particular incident is before we jump to those conclusions and labels. The crucial issue for us is that, on the basis of the information we’ve had indirectly from victims, clearly criminal offences have been committed. What we need to do now is to understand that in much more detail.”
Some 47 officers are working on the inquiry, launched after one of the women contacted staff from the Freedom Charity last month. The three eventually left the house in Brixton, south London, where they said they were being held.
According to reports, the women had been taken in by the man known to activists as “Comrade Bala”.
Ms Wahab recently suffered a stroke but was not receiving treatment, and it was reportedly this which pushed the women to seek help.
Mr Rodhouse added that his team have requested court papers from the 1997 inquest into the death of Sian Davies, who was fatally injured when she fell from a window of a house used by the political group in Herne Hill, south London. Police were not called to the house at the time of her death, but Mr Rodhouse is looking at inquiries which officers carried out on behalf of the coroner, who reached an open verdict.
“We have retrieved the court papers, the inquest papers, and we are in the process of reviewing those to see what they can tell us about the police involvement in that inquiry,” he said.