SYDNEY — An Australian underworld matriarch was found guilty Wednesday of orchestrating an execution-style murder of her brother-in-law as he enjoyed his daily coffee at a busy suburban cafe.

Judy Moran, a 66-year-old grandmother, was convicted over the slaying of Des "Tuppence" Moran who died from multiple gunshot wounds to the head in Melbourne in June 2009, in a case police described as too far-fetched for television.

Shot at noon at close range by two balaclava-wearing gunmen, the former underworld enforcer was from a family that played a key role in a deadly years-long gang war for control of the city's drugs trade.

Judy Moran had already lost two husbands and two sons in the gang war, which claimed about 30 lives after it began in the 1990s and was dramatised in the hit Australian series "Underbelly", likened to US show "The Sopranos".

Moran, who uses a motorised wheelchair, subsequently traded on her notoriety as a gangland "black widow" with frequent television appearances portraying her family as unwitting victims of underworld violence.

Dressed in black with her lips painted bright red, Moran clasped a tissue between her hands and bowed her head as the jury delivered the verdict after seven days of deliberations at the Supreme Court.

She smiled and waved to photographers on her way into the prison van, escorted by six security staff, witnesses said. She has not yet been sentenced.

It was alleged during the trial in Melbourne that Moran plotted with gunman Geoffrey Armour to kill her 61-year-old brother-in-law and that she drove the getaway car to and from the murder scene.

Armour has already admitted murder and the other gunman, Michael Farrugia, pleaded guilty to manslaughter and was jailed in December for four years.

Farrugia testified against Moran in court, as part of a plea deal, and said she had congratulated the gunmen when they returned to the car, the ABC reported.

"Did you get him?" Farrugia said she asked. Then Moran said "well done" and patted the gunman on the back.

"She was in control," Farrugia was quoted as saying.

The jury heard the weapon and clothing worn by the gunmen were hidden in a safe at Moran's home and the getaway car was in her garage.

Prosecutors said her plan was motivated by an ongoing financial dispute she had with her brother-in-law, who she believed was swindling her out of millions of dollars from business dealings involving her late husband Lewis.

But the widow said she was visiting the grave of her slain son Mark on the morning of the killing and had no motive to harm Des Moran.

The defence painted a picture of a grandmother whose life had been ripped apart by the underworld, who commemorated her dead relatives with potted roses in her backyard and talked to them over a cup of coffee, ABC said.

"She does cemeteries. She tends graves. She has memorials. She speaks to people who are dead but for her not gone," her lawyer Bill Stuart was quoted as saying in court.

After the high-profile trial came to a close, Stuart told reporters outside court he felt "disappointment" at the verdict.