A 41-year-old man has appeared at Dún Laoghaire District Court charged with the murder of Elaine O'Hara.
Graham Dwyer, of Kerrymount Close, Foxrock in Dublin, was remanded in custody until Friday 25 October.
He was charged with the murder of Ms O'Hara at an unknown location in Dublin on 22 August last year, which is the day she went missing.
The remains of Ms O'Hara, who was 36, were found in the Dublin Mountains last month.
The architect had been questioned for 24 hours about the murder.
The father-of-two was questioned through the night by gardaí, after deciding not to rest.
After being charged, Mr Dwyer was taken by detectives from Blackrock Garda Station to Dún Laoghaire for his court appearance.
Detective Sergeant Peter Woods gave evidence of arrest, charge and caution.
He told the court that when the accused was charged and asked had he anything to say in reply to the charge, he said: "I do, not guilty."
Mr Dwyer did not speak during the brief hearing.
An application for free legal aid was deferred, but the detective sergeant told the court there was no garda objection to this.
"I am aware of his financial background," he said.
Because the charge is one of murder, any application for bail will have to be made to the High Court as the District Court does not have the jurisdiction to grant it.
Judge Bridget Reilly remanded Mr Dwyer in custody to appear again at Cloverhill District Court next week.