Ian Bailey claims the murderer of Sophie Toscan du Plantier died a long time ago.
The former journalist is calling for a cold case review of the crime - which he says will clear him.
No one's been charged here with the murder of the French film-maker in west Cork nearly 25 years ago.
Mr Bailey was convicted in his absence in Paris in 2019 - but he claims the real killer has passed away.
"There's somebody in Ireland knows it wasn't me. I don't know if anybody knows who it was, I suspect there are people who do know who it was.
"Is the killer still alive? If my own theory is correct, and I can't say too much about it, the murderer is dead, and has quite a long time ago passed way."