Karen pictured with her husband Borce in this undated photo.
Inmates of Melbourne Assessment Prison reportedly bashed alleged killer Borce Ristevski on his first day in jail where he is being held while awaiting trial over the death of his Kiwi-born wife.
The 53-year-old was assaulted in the prison yard but the attack was not believed to have been severe, according to The Age.
Ristevski is currently being held in a protection unit at the facility.
Corrections Victoria confirmed a 53-year-old prisoner had been treated for minor injuries following an assault at the prison on Thursday afternoon.
"He did not require hospitalisation and was treated in the prison medical centre," the spokesman said in a statement.
Ristevski faced Melbourne Magistrates Court on Wednesday charged with his wife's murder, hours after he was arrested by detectives.
He is accused of murdering his 47-year-old wife at Avondale Heights on June 29, 2016, according to documents tendered to court.
Dressed in a white T-shirt and sporting a thick beard, Ristevski, spoke just one word during an appearance at Melbourne Magistrates' Court on Wednesday that lasted a total of four minutes.
Asked if he had had the opportunity to speak with his lawyer Rob Stary that morning, Ristevski answered "yes".
His lawyer Rob Stary indicated his client would be pleading not guilty.
Prosecutors have been granted extra time to prepare their case because of the complex nature of the investigation, according to the Herald Sun.
Ristevski was arrested at 7.20am by detectives from the Missing Persons Squad, a Victoria Police spokesman said.
Ms Ristevski went missing from the couple's $1.1 million Oakley Drive mansion on June 29, 2016. Her remains were discovered in bushland in the Mount Macedon Regional Park almost eight months later, on February 20.
Mr Ristevski has told police she went for a walk to "clear her head" following a minor argument about money but never returned. He reported her missing the next day.
Her remains were found wedged between two logs off a walking trail at Mount Macedon in Melbourne's north west on February 20. Police have never released the cause of death.
No one from their families were present when Ristevski appeared in court on Wednesday.
Ms Ristevski's brother Steve Williams later released a statement to media.
"Today has been a surprisingly emotional day — one in which I have been patiently waiting for," Williams said.
"It is no way a celebration, it's another stage in bringing my beautiful sister Karen the justice she so deserves." Ristevski has been remanded into custody and is scheduled to return to court on April 18.