A witness told the Court of Appeal that two men plotted to kill Allan Ames and bricks of his stolen meth were found in the house of a man who made an alleged deathbed confession to the murder.
Daniel Troy Ames, 49, is serving a minimum sentence of 24 years for the murder of his 68-year-old uncle at his Cavan workshop in 2009.
He was convicted in 2011 by a judge.
The sentencing judge found that Ames had no motive to kill his uncle and the murder weapon had never been found.
Ames has launched his last avenue of appeal on the basis of fresh and compelling new evidence he confessed to the crime by Peter Lagerwey before he died in 2016, and the failure of police to disclose information ahead of his trial.
The court has previously heard that Lagerwey, a drug trafficker, told a friend in the days before he died of cancer that he had killed Mr Ames.
The appeal was reserved last month by Justices Mark Livesey, Sophie David, and Chris Bleby, but lawyers for Ames and the prosecution asked for it to be reopened after more information came to light.
A witness, who can't be named for legal reasons, was called to give evidence, telling the court of a conversation with Lagerwey - who was violent on and off meth ahead of the murder in 2009.
Lagerwey said he and Danny were going to do the murder for drugs, the witness told the court today.
Lagerwey said he changed his mind about the plan.
Tom Cox KCCox KC, for Ames, asked the witness if the conversation about murdering Mr Ames came as a surprise.
After the murder, the witness said that a lot of meth had been found in sealed bricks the size of a standard tissue box on Lagerwey's kitchen bench, along with a silver gun.
Peter said that Danny was now a millionaire.
Cox questioned the witness about trying to shield Lagerwey from the responsibility of the murder.
The witness said he was not here to protect anyone but tell the truth. The witness told the court that Lagerwey had stolen drugs from the murder scene, along with the weapon.
The court heard evidence from a former Yatala prisoner who was in jail at the same time as the witness's relative.
The inmate, who could not be named for legal reasons, said he started talking to a fellow prisoner, who said his relative had been involved in a murder. The former inmate told the appeal court he believed that someone else had been convicted of the crime.
Prosecutor Jim Pearce KC suggested to the prisoner that he was lying about that conversation he had had in jail in 2011.
The prisoner responded, That's not true, that's definitely not true.