Sian Davies - who is thought to be Rosie's mother - is understood to have lived in the commune for more than 20 years
Last night detectives were examining inquest reports into her death in October 1997.
Rosie has told neighbours that her mother died and she was adopted by the suspects.
But the identity of her mother and circumstances of her death remain unclear. One neighbour who remembered the family living in Herne Hill said an older woman had died falling out of a window there.
She said: ‘One day the police came and told me an older woman living in that house had died falling out of a window at the back.
'They asked if I had seen anything.
'I said no and they never got back to me.’ Sian Davies, who was living with the family at the time of her death in 1997, is known to have joined the Maoist communist collective that Balakrishnan ran.
In 1978, she was one of six young militant women arrested when police raided their headquarters in a bookshop in Brixton.
A local newspaper report of the case reveals the group’s extremist views as the women chanted slogans calling for the ‘downfall of fascist Britain’ throughout their trial.
The shocked judge in the case, Judge Hayan, said he had never come across such bigotry during the proceedings.
The Mail can reveal her identity after police confirmed there is no evidence she was sexually abused
It also emerged last night that a woman who may have been 30-year-old Rosie's mother died in mysterious circumstances at a property where the alleged captors previously lived with two other 'slaves'
All six refused to enter pleas on 13 charges of obstructing or assaulting the police saying they ‘did not recognise the court, the judge or the jury system’.
The women also refused to let police search the Brixton property for drugs and chanted ‘Death to the fascist state.’
One of the communists, Aishe Waham then 34, read a prepared statement saying that the British were the lackeys of the Americans.
The report went on: ‘At the end of her speech the six chanted together with upraised right arms and clenched fists.
‘They said they were political prisoners facing trumped up charges.’
Yesterday it emerged that Balakrishnan, and his wife, originally from India and Tanzania, were well known to the police and security services.
Described as a ‘guru’, the economics graduate was said to be a powerful figure who had a tight-knit band of devoted female followers under his ‘spell’, most of whom were persuaded to give up their studies in order to ‘integrate with the working class’ and carry out ‘revolutionary work’.
Known as ‘Comrade Bala’, he came to police attention after setting up a communist squat, the Mao Zedong Memorial Centre, in Brixton in 1976 where the couple ran their group, the Workers’ Institute of Marxism-Leninism-Mao Tse Tung Thought, holding lectures and film evenings.
Two years earlier, he had been kicked out of the Communist Party of Great Britain’s national executive after his faction ‘attempted to put themselves above the discipline of the party’ (the party was broken up in 1991).
By the time of the Brixton riots in 1981 their organisation had gone underground where it remained for more than 30 years.
Kind gift: Alleged prisoner Rosie knitted neighbour Jesse Paddy a jumper, who said he did not know anything about alleged slavery in the property
Note: Rosie, 30, gave this warm handwritten message to with the garment earlier this year for Mr Paddy
Accusations: Eleri Morgan has told ITV News her cousin Sian Davies lived within the collective led by slavery suspect Aravindan Balakrishnan, who she described as a 'toothless old man'
This site in Brixton was once the headquarters of the Mao Zedong Memorial Centre - which housed a communist collective run by the slavery case suspects - reportedly Aravindan Balakrishnan, 73, and his wife Chanda, 67
MALAYSIAN WOMAN SAYS ELDEST 'SLAVE' IS HER MISSING SISTER
A Malaysian woman has claimed one of the women allegedly held against their will in south London for 30 years is a relative.
Kamar Mautum, a retired teacher from a town near Kuala Lumper, told the Daily Telegraph that the 69-year-old captive, who they name as Aishah, is her sister.
According to Kamar she had moved to Britain with her fiancé in 1968 but got involved in extremist politics before disappearing without trace.
They were drawn towards an extremist Maoist organisation, called the Malaysian and Singaporean Students Forum, and became embedded in the politics at the time.
The Maoist group was at the forefront of many student protests, especially over the war in Vietnam.
Her disappearance had caused extreme heartache for her family and her mother’s dying wish had been to know whathappened to her daughter.
Last week Aravindan Balakrishnan and his wife Chanda were arrested last week arrested on suspicion of holding three women captive.
‘I have felt so choked without her for years and years. She was so talented, she was the apple of my mother’s eye. She asked for her on her death bed.’ Kamar told the Telegraph.
She said her sister became more and more drawn to the leader of the collective leading her to leave her fiancé.
Following an argument over her allegiance to ‘Chairman Ara’, or ‘Comrade Bala’ as he was known, she threw her engagement ring into the River Thames.
According to Telegraph she disappeared without trace in the early 1970s, moving in with the small Marxist cell which regularly moved between squats and council home.
