Waden was questioned over the murder of his girlfriend, Priscilla Brooten.
Nine can reveal never-before-seen evidence from the trial of Mark Sheridan Waden, convicted of murdering his ex-girlfriend in Brisbane in 2018.
Police asked Waden about his girlfriend after she went missing from their home in Brisbane's north.
The case was eventually a circumstantial one, with no body, no eyewitnesses and no crime scene. So, detectives asked, what happened to Brooten?