No evidence can confirm claims that the son-in-law of missing World War II veteran Leslie Ralph Ball killed him at his north Queensland home, an inquest has heard.
But a detective says he believes David Phillips had some involvement in his 73-year-old father-in-law's disappearance.
Mr Ball, a retired builder who served with the Royal Australian Air Force in Darwin, was reported missing in Townsville in May 1993.
Family friend Brian Murphy told the re-opened inquest into Mr Ball's disappearance that Mr Phillips confessed in the 1990s to killing his father-in-law in his garage in retaliation for "indecently dealing" with a girl.
Detective Senior Sergeant Chris Knight told the coroner on Tuesday no forensic evidence was found at the Townsville house to back up Mr Murphy's claim during a 2017 review.
Inquiries were also made to identify a "mystery person" after Mr Murphy claimed Mr Phillips killed another man who helped dispose of Mr Ball's body and buried them "in the same grave".
"I believe that statement from Brian Murphy is credible (but) we were unable to find anything to validate those details allegedly said by David," Det Sen Sgt Wright said.
However, he agreed Mr Phillips - who died in 2015 - was the "most likely suspect" based on opportunity and inconsistencies in his statements.
A 1990s inquest closed after the coroner was unable to find Mr Ball's disappearance was due to foul play but reviews were held and witnesses interviewed again.
A 2017 report containing new findings was submitted to the Coroners Court and the inquest was re-opened at the attorney-general's direction.
"I recommended that David Phillips should be identified (in the 2017 report). I do believe he had some involvement in Leslie Ball's disappearance," Det Sen Sgt Knight said.
"Whether that was murder or a cover-up, that is my recommendation ... and I maintain that opinion to this day."
He believed Mr Phillips and his wife - Mr Ball's daughter Leanne Phillips - had "constructed lies" throughout investigations into the WWII veteran's disappearance.
Ms Phillips told the inquest that the last time she saw her father was when he visited her in a Brisbane hospital in April 1993.
Mr Ball's car was found abandoned at a train station car park.
However, Det Sen Sgt Knight said experts had confirmed a train ticket to Brisbane discovered in Mr Ball's name was a forgery and Queensland Rail could prove no one travelled in that seat number that day.
"In terms of the account of Leslie Ball buying a train ticket, travelling to Brisbane, visiting her at hospital, leaving his car at the train station - I can't believe that account," he told the coroner.
"David and Leanne have maintained that account for many years.
"That remains to me ... a real sticking point in terms of involvement in or at least knowledge of some of the circumstances around Leslie Ball's disappearance."
Mr Ball's daughter Le-Chelle Lesley said outside court that sitting through the two-day inquest which concluded on Tuesday had been difficult.
"It was hard ... but you learn to live with it. What else can you do? It would send you crazy otherwise," she said.
Coroner Stephanie Gallagher will consider whether Mr Ball died and the identity of anyone involved in his disappearance or death.
She will deliver her findings at a later date after considering submissions to be received by next month.
"We are still looking for answers. Hopefully ... the coroner can give some ... closure to the family," family member Ross Ball told reporters.
