VINCENT O'Dempsey will not give evidence at his Supreme Court trial for allegedly killing Barbara McCulkin and her two children more than 40 years ago.
The prosecution case against the 78-year-old has closed on the 11th day of the trial at the conclusion of evidence from a prison informant and a police officer.
Mrs McCulkin, 34, and her daughters Vicki, 13, and Leanne, 11, were allegedly murdered by O'Dempsey and Garry Dubois when they went missing from their Highgate Hill home in January, 1974.
O'Dempsey, 78, has pleaded not guilty in the Brisbane Supreme Court to three charges of murder and one count of deprivation of liberty, while Dubois has a separate trial.
When O'Dempsey was asked today whether he would give or call evidence, his barrister Tony Glynn QC answered on his behalf that he would do neither.
It is a defendant's right not to appear in the witness box and that decision cannot be used against a person facing trial.
The jury has now been dismissed for the day and will return on Monday to hear closing submissions from the prosecution and defence.
Earlier today, a prison informant denied he invented a conversation with O'Dempsey in which he allegedly admitted to having a role in the infamous cold case.
"I suggest to you that at no time did Mr O'Dempsey tell you that he had played any role in the disappearance or killing of the McCulkins," Mr Glynn asked the witness.
He replied: "No, I disagree with that entirely".
The witness also disagreed with Mr Glynn's suggestion that O'Dempsey "never indicated ... an intention or desire to harm any person."
More than 50 witnesses have given evidence since the trial started on May 2.