Crime figure Pasquale Barbaro may have been gunned down in Sydney because he was talking to the authorities, according to a journalist who's written a book on the Barbaro family.
Journalist Keith Moor says the latest Barbaro to die might have been killed for the same reason his grandfather was - he may have been talking out of school.
"The homicide squad will be looking at whether the Calabrian mafia decided themselves to silence Pasquale Barbaro because the suggestion is he was breaking the code of omerta and had become an informer," the author of Busted told AAP on Tuesday.
Sydney police found Barbaro on a suburban footpath in Earlwood after being alerted to a shooting just before 10pm on Monday.
Moor says the 35-year-old was "born into the Calabrian mafia.
"It's passed on from father to son to cousin," the journalist said.
"There have been a lot of criminal Barbaros ... and in particular a number of Pasquale Barbaros who have been members of the Calabrian mafia and involved in crime."
The Pasquale Barbaro shot on Monday was due to face court in Sydney in December on drug charges.
His grandfather Peter Pasquale Barbaro was gunned down in Brisbane in 1990 just before he was due to give evidence against almost 30 mafia figures.
A cousin, also called Pasquale Barbaro, was shot dead in a Melbourne car park in 2003 while working as Jason Moran's bodyguard.
And an uncle, yet another Pasquale Barbaro, from Griffith, was the kingpin in the world's biggest ecstasy bust. He was sentenced in Melbourne to 30 years in jail in 2012.
That drug trafficker's father was a suspect in the murder of Donald Mackay in Griffith in 1977.
Moor believes Monday night's shooting could be difficult to solve because traditionally the mafia are reluctant to talk to authorities.
He thinks the Barbaro family will instead conduct their own "investigation" into what happened.
The journalist said the problem for police trying to crack down on the Barbaros was that as soon as one was knocked down, another seemed to pop up.
The mafia in Australia are involved in drugs, extortion rackets and illegal prostitution, experts say.
Monday's slaying comes two weeks after another Sydney crime figure, Hamad Assaad, was shot dead outside his Georges Hall home.
Pasquale Barbaro survived a shooting in the inner-western suburb of Leichhardt a year ago and it's been reported Assaad was a suspect in that non-fatal shooting.