Comancheros boss Tarek Zahed remains in a serious condition in hospital after he was struck by 10 bullets at a gym in Auburn in western Sydney on Tuesday night.
His brother, Omar, died at the scene.
The attackers remain on the run, with two burnt-out cars found in nearby suburbs following the shooting.
Police revealed yesterday that the Zahed brothers had been warned they were being targeted.
Assistant Commissioner Michael Fitzgerald said the pair had been warned as recently as last Thursday they were marked men, but neither chose to take any extra precautions or protections.
Retired detective Peter Moroney told Today this morning that “clearly” the brothers were wrong in thinking they were protected from an attack.
“That’s just the type of people that we deal with,” he said.
“We’re forever telling them or warning them. If we’ve got credible intelligence, it is told for that reason but if they choose to ignore it, what do you do?”
He said it was “going to be difficult” for police to track down the shooters due to the “very violent organised crime element” of the attacks.
“Twenty-odd shots into an individual at 8 at night in middle suburbia, there is no other explanation for it.”
He said tip-offs and leads in investigations were “drastically reduced” with such organised crime.
Homicide Squad Detective Superintendent Danny Doherty yesterday confirmed one line of inquiry police were pursuing was whether this latest shooting is linked to ongoing conflict between crime networks in west and south-west Sydney.
He said detectives are looking at whether a “power struggle within criminal networks” was at play and said they are not discounting any previous incidents.
NSW Police Commissioner Karen Webb said officers “won’t rest” until the conflict is resolved, and her “greatest fear” is “an innocent member of the public will be killed”.