The prosecution says an elderly man accused of the ''exceptionally violent, brutal and frenzied'' murder of a neighbour should remain behind bars because it's still unclear what prompted the alleged crime.
But lawyers for Luigi Costa have argued their client should be bailed to a psychiatric centre because he may have Alzheimer's and is unlikely to stand trial before the middle of next year.
Costa will on Saturday celebrate his 70th birthday behind bars at the Alexander Maconochie Centre, where the court heard he has been spotted singing arias from a ''well-known Italian opera'' in the nude.
The Red Hill man has been committed to stand trial in the ACT Supreme Court for the alleged stabbing murder of 89-year-old Terrence Freebody who lived across the road.
Costa has been locked up on remand since July when police allege that he killed Mr Freebody at Costa's Mugga Way home.
Officers responding to a triple-0 call, allegedly from Costa, found Mr Freebody on the dining room floor and the accused man in a bathroom.
Defence barrister John Purnell SC, on Friday asked Justice Richard Refshauge to bail his client to the Calvary Hospital's private psychiatric ward for treatment.
It was Costa's second bid for bail, after a long, unsuccessful application in the ACT Magistrates Court.
The defence are seeking a gerontologist's report so a forensic psychiatrist can assess his fitness to plead.
The court has previously heard other psychiatrists suspect Costa has Alzheimer's and possibly an alcohol-related condition.
Mr Purnell argued the likely delay in going to trial, his client's offer to put up a substantial surety and Costa's age and apparent infirmity justified his release.
But prosecutor Anthony Williamson opposed the man's release.
He described the alleged killing as an ''exceptionally violent, brutal and frenzied attack'' and noting the reason for the incident was unclear.
''If we don't know why he did it this court must have concerns that he would do it again,'' he said.
''If we knew why we could address these risk factors, but we don't, so we can't.
''The risk remains at large, and it's an appreciable risk in my submission.''
Justice Refshauge will hand down his decision on Monday.