LONDON -- British police investigating a slavery case involving three female victims say they are investigating 13 London addresses linked to the two suspects.

Police said Monday that inquiries into the new addresses followed an extensive search of an apartment in the Brixton neighbourhood of south London.

The Metropolitan Police also said that the male suspect is 73, not 67 as previously reported. The female suspect is 67.

One suspect is from India and the other from Tanzania, but police did not specify which individual came from which country. Police have said they shared a political ideology with the three victims, who were allegedly held against their will for 30 years.

Police have said the victims initially lived with the suspects as part of a collective but refused to provide details about their beliefs.

British press reports Monday indicated the group was part of an extreme Maoist collective that operated in the late 1960s and 1970s.

Britain's Press Association said they were active in the Mao Zedong Memorial Centre, which was raided by police in 1978.

Steve Rayner, a professor at the University of Oxford who has studied the Maoist movement extensively, said in a statement Monday that they constituted a tightly-knit group that "refused to recognize the legitimacy of the state" and maintained a hostile attitude toward the establishment.

He said he had thought they had "sunk without trace" until this case surfaced last week.

Police had earlier indicated that the two suspects had been arrested in the 1970s but would not say why.

The alleged victims are a Briton, 30, an Irishwoman, 57, and a Malaysian, 69. They are said to be receiving extensive counselling at an undisclosed safe house.

Police have said they do not appear to have been subject to sexual abuse but were beaten and subjected to brainwashing. Police said "invisible handcuffs" kept them from fleeing until one of them contact a charity seeking help last month.

The two suspects were arrested last week and are free on bail until a court hearing in January.