Mark Stephen Murphy is accused of murdering unemployed construction worker Gregory James Thurlow in north Brisbane in October 1996.
Prosecutor Rhys Dunmall handed up 48 statements and an exhibit list to Brisbane magistrate Peter Saggers during brief committal proceedings on Tuesday.
In response Murphy’s legal aid lawyer Thomas Schafer agreed there was enough evidence for the case to be committed to the Supreme Court.
Asked by Mr Saggers whether he wanted to say anything in answer to the charge, Murphy replied that he was guilty.
The admission was in accordance with Murphy’s instructions to Mr Schafer, the court was told.
Mr Thurlow was last seen leaving a Bray Park home in a green 1980 VC Holden Commodore sedan late on October 1, police said previously.
Investigations found Thurlow and a male associate were in the vehicle when it stopped along Anzac Avenue in Mango Hill, with police alleging the 27-year-old was killed shortly after.
Detectives arrested Murphy, of Burpengary East, in September last year following a six-month investigation by a cold case investigation team.
This included re-interviewing witnesses, re-examining forensic exhibits and a search of an area of interest near Mango Hill.
New information was received after a billboard was placed in the area and targeted social media posts encouraged people with information to come forward, police said at the time of Murphy’s arrest.
Murphy remains in custody ahead of his sentence in the Brisbane Supreme Court on a date yet to be set down.