Murdered Brisbane rugby league referee 'wanted to leave will to prostitute'

A Brisbane rugby league referee murdered in a "cold-blooded execution" had planned to leave his entire estate to a brothel madam he thought was his fiancé, a court has heard.

Tony McGrath, 57, was found dead with a gunshot wound to his head in the garage of his Woolloongabba home in May 2013.

Tyson John Taylor pleaded not guilty to murdering Mr McGrath on Tuesday.

Geoffrey Mines, a solicitor and long-time friend of Mr McGrath, said yesterday his friend contacted him in August 2012 wanting to change his will, the ABC reports.

Mr McGrath's previous will had named his sister Carmel Ward as sole beneficiary, but he wanted it changed to only name prostitute Susan Stewart.

Stewart, who ran a brothel in Tweed Heads, has also been charged with Mr McGrath's murder.

"In the first instance he wanted to leave it to any children that he and Susan might have together, or if there were no children to leave it to Susan," the ABC quotes Mr Mines as telling the Brisbane Supreme Court.

"If Susan didn't survive, to leave it to Susan's three children from a previous relationship."

The new will was never signed by Mr McGrath.

Mr Mines told the court Stewart "probably" believed she had been named in the will.

Tyson Taylor was also in love with Stewart at the time of the murder, Crown prosecutor Vicki Loury told the court.

"She was a woman who cynically manipulated both men, ultimately out of pure greed," Ms Loury said.

Ms Loury told the jury earlier this week Taylor had confessed to the killing after becoming involved in a covert police operation in 2014.

"(It) was nothing less than a cold-blooded execution," Ms Loury said.

Mr McGrath had been allegedly drugged before his house was deliberately set on fire in October 2012.

Ms Loury said Taylor had opted to use the "far more effective means" of shooting Mr McGrath in the head after he survived the fire.

Mr McGrath had given Stewart more than $550,000 before he died.

Invoices found at Stewart's house suggested Taylor had spent more than $20,000 on her services between August 2008 and February 2009, Ms Loury said.

An analysis of Stewart's finances showed a total of $1.1 million had been transferred to her by three different men between July 2009 and May 2013.

The trial continues.