A statement made to gardaí by Cynthia Owen's niece, Theresa Murphy, in which she detailed allegations of abuse, was read to the inquest.
Ms Murphy, the daughter of Cynthia's sister, Margaret Stokes, was raised by her grandparents, the late Josephine Murphy and Peter Murphy snr, the court heard. She committed suicide in 2005.
Her statement, which was made in 1995, alleged that a woman in the family home in Dalkey took turns at forcing herself and another brother, Michael, also deceased, to sleep in bed with a male member of the family against their wishes.
Her statement, made in 1995, said the man would push them against the wall so they "couldn't get out".
In the statement she said that he used to "masturbate" while she was in bed beside him and also touch her inappropriately.
Ms Murphy's statement continued that she was "very frightened" by this abuse and "felt rejected" by the woman who was forcing herself and her brother to sleep in the same bed as this man.
Ms Murphy left an extensive suicide letter detailing the sexual abuse she alleges took place, the court heard.
Catherine Stevenson, another of Cynthia Owen's sisters, alleged to gardaí that she was "sexually abused" by a man referred to as D, Garda Dominic Hearns told the inquest.
The ex-partner of another of Cynthia Owen's sisters, Frances Murphy, told the inquest yesterday that one of her female relatives, referred to as B, came at him with a scissors and swiped at him with a knife on another occasion. Ken Walsh told the inquest that the woman became "angry" that the couple had broken up and called into his home in Sallynoggin, south Dublin. "She said Frances was sick and would I get dressed and come down. We were walking down the path and my mother shouted 'watch your back' or something like that. When I turned around, B was coming towards me with a scissors. I just ran off out the gate," he said.
In a separate incident, he said the woman "swiped a knife" at him before he grabbed it from her hand. He added that the woman used to walk around her house carrying a hammer that she would occasionally "tap" him and other guests with, which he found "strange".
Mr Walsh said he "knew Frances was abused" and had "no reason not to believe" other allegations made.
Coroner Dr Kieran Geraghty told the inquest that Peter Murphy snr and his daughter Catherine Stevenson would not give evidence at the inquest due to illnesses. The inquest continues today.