Ruth and Ken Nash were married in 1956, and moved into 12 Waratah Street Chatswood in the same year. Ruth Nash said at the Inquest that she had known the Bogles for some time, but had not met the Chandlers until 21st December 1962. Following the CSIRO (Commonwealth Scientific and Industrial Research Organisation) barbeque at Murraybank, the Chandlers, as well as the Paytens and Isabella Margaret Beavis, were invited to the Nash house. It was here that the Chandlers, and Miss Beavis, were invited to the New Year's Eve party.

Each guest had been invited to bring along a piece of art of their own creation. When the guests arrived at the New Year's Eve party, they were greeted by Ruth Nash, who pinned a red paper star to guests' artwork, and red lapel badges shaped like an artist's palette to the guests themselves. Ruth Nash had prepared these herself.

Ruth Nash first noticed that Geoffrey Chandler was absent after midnight. She did not see his car where she remembered him parking it. She then looked for Margaret Chandler, whom she saw standing on the back lawn with Bogle.

Someone put on a record, In a Little Spanish Town. Bogle started dancing to the music in flamenco style, and was joined by Ruth Nash. She wore a mock frown and stamped her feet to the music. She left the room and soon returned with a pair of castanets.

At some time between 2:30am and 2:45am, but probably closer to the latter, Ruth Nash saw off Frances and Leicester Cotton, the first to leave. Supper had not yet been served, so she passed them each a chicken leg to chew on. When she returned inside, she saw Mr Chandler again, for the first time since she'd noticed him missing.

At 3am Ruth Nash served supper from the kitchen, assisted by Mrs O'Donnell and Mrs Rudd. At 3:30am she served coffee.

Ruth Nash testified that about 5 minutes had elapsed between the time Bogle waved goodbye to her, and the time she saw Mrs Chandler on the steps. Isabella Margaret Beavis left before Mrs Chandler. At the time of Mrs Chandler leaving, the house and street lights were still on. It was not substantially daylight at 4:30am. After Mrs Chandler's departure, it was more than an hour before anyone else left the party. Mrs Nash added that neither Mr nor Mrs Chandler thanked her for the evening before departing.

After giving her evidence at the Inquest, Ruth Nash continued to attend every day. She dressed differently each day (it was rumoured that she made her own clothes), and hence she was much photographed. Every day she sat behind the bar table, taking notes. It was rumoured that she was going to write a book about the case, which never eventuated. Sergeant Don Goode was so used to seeing her that he once turned to her to check a word that a witness had used.

Ruth Iris Nash died on 1st January 1974, exactly 11 years to the day after Dr Bogle and Mrs Chandler.