See more of Anthony Rickard's shocking claims here..
"I think he acted - not on purpose - but he did obviously choke her. She's a tiny woman. Just a little squeeze would've been enough," he said.
Mr Rickard claimed Karen was preparing to leave her husband, which he said would have "left him in a big hole financially" as the Ristevski family home is in her name.
Borce Ristevski strenuously denied any involvement in his wife's death until he shockingly pleaded guilty to manslaughter on March 13, the night before his murder trial at Victoria's Supreme Court was due to commence.
Mr Rickard claims he is responsible for his father's confession, revealing he gave Borce "an ultimatum" to tell the truth by threatening to reveal he had been having a long-running affair with Karen before her death.
In a sensational twist, Borce and Karen's daughter Sarah turned witness for the prosecution shortly before his admission.
Daily Mail Australia revealed Sarah was "surprised by the sudden guilty plea" and had not expected it.
Ristevski is due back in court on Wednesday for a plea hearing.
Karen Ristevski, 47, vanished from the family home in Avondale Heights just outside Melbourne in June 2016.
Her body was discovered in a shallow grave in Macedon Regional Park over eight months later, too badly decomposed to determine a conclusive cause of death.
Because of his manslaughter plea, Ristevski will avoid a life sentence and instead faces a maximum of 20 years' imprisonment for his wife's death.
