Torsten Trabert and his co-accused John Ryan have pleaded not guilty in the Supreme Court to murdering Wayne Amey in a case where the Crown claims the men agreed to kill Robyn Lindholm's former boyfriend because they were infatuated with her.

Chief Crown prosecutor Gavin Silbert, QC, has told the court Ms Lindholm saw herself as a femme fatale who could manipulate men to do whatever she wanted.

Mr Silbert said Ms Lindholm had had a tempestuous relationship with Mr Amey and wanted him dead so she could keep their farm at Bittern after they had broken up.

Mr Trabert had left his wife and children for Ms Lindholm and the couple had been involved in an intense sexual relationship when he agreed to kill Mr Amey, the prosecutor claimed.

After his arrest, Mr Trabert was being held on remand when he met another prisoner named Raad Ajil.

Mr Trabert told Mr Ajil in March 2014 how he had been charged with murder and that he had killed the victim "who flew across the car park and that he had buried him", the prosecutor said.

"Trabert told him that he had taken drugs prior to committing the murder in order to be like a Superman."

Mr Silbert said Mr Trabert later sought help from Mr Ajil, whose uncle was a spiritual adviser of some sort, and Mr Ajil convinced Mr Trabert he could help him if Mr Trabert told him exactly what had happened.

The prosecutor said Mr Trabert then wrote down an account of what happened and gave it to Mr Ajil.

"Precisely what Trabert was expecting to gain from this is not entirely clear," Mr Silbert said.

"Somehow Trabert hoped for some black magic to assist him with his matrimonial difficulties at the time and with his murder charge."

Mr Silbert said the document handed to Mr Ajil by Mr Trabert read: "Me and John Anthony Ryan went to Wayne Amey's place. John got him with a taser and Wayne started to fight back, so I got out of the car and started to hit Wayne and I knocked him out and then I dragged him to his car. John put him in the boot after tying him up.

"I drove the four-wheel drive. John was in a Ford with Wayne in the boot. Johnny followed me around and when we stopped he said that Wayne kept opening the boot so he kept hitting him with a baseball bat to stop him and shut him up. Then we went for a drive and Johnny pulled out a pen pistol to shoot him but it did not work, so he stabbed him and then he strangled him till he wasn't breathing any more.

"All I wanted to do was go home so he dropped me off at the house and I didn't see him until Thursday morning after my daughter's school concert. I met him in Kyneton Springs. I was on my bike and so was Robyn. Got in the four-wheel drive and he said the body was in the back of it. Robyn told me that he raped her so I hit him three times with a baseball bat there. I hit him and kicked him as well there. I put caustic soda on his face before John Ryan killed him."

Mr Amey, 54, was attacked in the underground car park of his Hawthorn apartment block just after 11.20pm on December 10, 2013, placed in the boot of a car and driven away.

Mr Amey's body was found wedged between boulders on Mount Korong, in central Victoria, on December 18. He had suffered four stab wounds to the chest, fractured ribs, multiple lacerations to the head and been choked with a blue rope.

Mr Trabert and Mr Ryan have both accused each other of killing Mr Amey.

Justice Lex Lasry told the jury on Wednesday that Ms Lindholm's case was being dealt with separately and the reasons why need not concern them.

The trial continues.