Video reveals 'vicious' killer's lies

A chilling video message has revealed how a man convicted of stabbing his former mistress to death tried to spin the brutal crime as an accident.

The video, revealed on 60 Minutes, was recorded by Paul Mulvihill in March just days before a jury found him guilty of the "vicious" July 2012 murder of Rachelle Yeo.

Yeo, 31, was stabbed in her apartment on Sydney's northern beaches so savagely that she lost almost all the blood in her body.

But Mulvihill, 46, filmed the video for one of his daughters in an attempt to try and deflect the blame for the crime from himself.

"I want people to see this video message to understand that I'm telling the truth as to what happened that night," says Mulvhill in the video, staring straight into the camera.

Mulvihill claims in the video that Yeo "came at me" with the murder weapon, a Global kitchen knife, and "slashed me and caught me on the palm of the hand and then slashed at me a second time".

"Once Rachelle grabbed that knife ... it was never going to be a good result for one of us," he says.

But retired homicide detective Charlie Bezzina told 60 Minutes that Mulvihill is a "calculating killer" whose claims in the video are "absolute nonsense".

A NSW Supreme Court jury agreed, taking only two hours to find Mulvhill guilty of Yeo's murder in March. In April, he was sentenced to a minimum of 22 years in prison.

In sentencing Mulvihill, Justice Elizabeth Fullerton said he was guilty of a "vicious and sustained" attack on Yeo.

Mulvihill's wife Theresa told 60 Minutes that the murder revealed "a totally different life" that he had away from his family.

She described him as controlling and said she was "frightened" how he would react to her speaking publicly about the case, even though he is now behind bars.

"It's scary that you think you know someone and you don't. It's very scary," Ms Mulvihill said.