The notorious former leader of the Comancheros died in St George Hospital on Thursday evening after he was shot multiple times outside Rockdale’s Fitness First around midday.

Fredericka Bromwich, the mother of Hells associate Anthony Zervas who was beaten to death with a bollard in 2009, said karma had come back to haunt Hawi.

“Mick Hawi got what he deserved and good on those boys that did it,” Ms Bromwich told the Seven Network on Friday.

“It is karma because what you do in life comes back to haunt you.”

It comes as an expert on outlaw motorcycle gangs says the brazen execution of ex-bikie boss Mick Hawi represents a frightening escalation in public violence.

Criminology professor Mark Lauchs believes the killing could trigger further violence in days or months to come in the form of firebombings or similar public assassinations of key bikie figures.

Mr Lauchs, from the Queensland University of Technology, says these public revenge attacks are inspired by a new generation of bikies taking the helm of organised crime in Australia who take their lead from gangs in the United States and violent TV series.

Far from leading low-key lives which include secretive criminal activities, today’s young bikies have no qualms about carrying out horrific attacks in broad daylight.

Ex-Comanchero boss Hawi was gunned down in the car park of the Rockdale Fitness First, in Sydney’s south on Thursday. He was shot at close range, possibly as many as a dozen times, as he sat in his black Mercedes and later died in hospital after numerous cardiac arrests.

NSW Police confirmed it was a “planned and targeted attack” and Assistant Commissioner Mal Lanyon told reporters the force is on high alert for possible retaliation in coming days.

The Daily Telegraph reports Hawi had a telephone “blow-up” with exiled Comanchero rival Mark Buddle before yesterday’s shooting.

News.com.au is not suggesting that Mr Bundle, who is overseas, was involved in Hawi’s death.

Professor Lauchs said nobody outside the closely-knit circle of people involved would know why this attack took place.

“This may be a traditional warfare hit between the clubs or it may be that (Hawi) has been involved in other things since he has been out of prison,” he said.

“The problem is that, if it is an incident of club warfare, nobody is going to say anything about it.

“We’ve had cases where someone is lying in a hospital bed with a gunshot wound, his mates are standing around the bed, the police will ask: “Can you tell us anything about the shooting?’

“The victim says: ‘Have I been shot? Oh, I didn’t realise’. They will admit nothing because it’s club business.

“And no major club would let this (Hawi’s shooting) go without retaliation.”

Professor Lauchs believes around 80 per cent of the information given to police in relation to gang-related Sydney shootings is completely wrong.

“So, this is going to remain a mystery until somebody one day just spills the beans,” he said.

“To conduct a hit like this in broad daylight is extremely risky, so there may be evidence that will lead police to track this person down.

“It is going to be very hard without inside knowledge to know exactly what the reason behind this was.

“However, when there is a target execution like this, it is almost entirely related to organised crime — for example, someone owes someone money or nicked their spot.”

Retribution for Hawi’s slaying may happen immediately or could take months, but a young generation of bikies wouldn’t think twice about carrying out a public execution, says Professor Lauchs.

“If it was old-school bikies, we’d probably never know what happened,” he said. “The older generation dealt with violence in secret.

“So, if this is club-related, it has been carried out by people of Hawi’s generation or younger — they’re the ones growing up watching a different set of media and getting different ideas about what being a gangster is about.

“It is not surprising that someone has done this in public, because this new generation pick up these American ideas about public shootings and the drive-bys from the media.”

However, he added that if some kind of attack was carried out at Hawi’s funeral, it would be a “huge bikie faux pas” which has never been committed in Australian gang history.

Professor Lauchs said Hawi’s shooting may have been revenge for his involvement in a brutal attack at Sydney Airport in 2009 in which a rival bikie was killed.

The former Comanchero boss was jailed for five years for the killing of Hells Angels associate Anthony Zervas in the violent brawl.

Hawi was originally found guilty of murder, but his conviction was overturned on appeal and he pleaded guilty to the lesser charge of manslaughter.

He was released in 2015 after a board approved his parole based on his “satisfactory prison performance”.

“There could be retaliation in the form of firebombings of club houses or drive-by shootings of senior members of the clubs — which is exactly what led to the 2009 brawl in Sydney Airport,” said Professor Lauchs.

“The old-school bikies would never have had that brawl in the airport. They would never bring all that attention on themselves.

“But you see every new generation of gangsters being influenced by what they see on TV. So El Chapo, who was infamous in the 1970s and 80s, would watch Scarface and he would recreate it.”

He said young bikies coming up now are influenced by shows with “lots and lots of shootings” like the US drama series Sons of Anarchy.

“There’s no bikie bible or any written rules,” he said. “So they are getting their influences from different sources as all of us do.”

However, Professor Lauchs said the three years since Hawi left prison was a long time to wait for a revenge attack.

“He hasn’t exactly been in hiding,” he said. “But these attacks take a long time to plan.

“You got to sit back, make a plan, wait for an opportunity, watch people. Whoever did this, didn’t plan it in 24 hours.

“They have watched him for weeks and [were] studying his routine. It would have taken a long time to put together.

“One of the hardest things is to find someone who is willing to actually do it. If you’re going to do this in public, this person is going to take a major risk and go to jail for the rest of their lives. That could take forever.”

Mr Buddle, who is overseas and reported to have rowed with Hawi in recent weeks, is wanted for questioning over the fatal shooting of Sydney­ security guard Gary Allibon in 2010.

Last year it was reported that Buddle texted gang members to say: ‘I’m the f***ing commander of the world ... no one is to touch another member or set up another chapter without my permission.’

Assistant Commissioner Mal Lanyon told reporters detectives were investigating Mr Hawi’s underworld links and who may have wanted him dead, while full resources are also being deployed to prevent retribution for the murder.

“It’s essential, when we believe there could be links to organised crime, that we take action to prevent that,” he said.

“This is something that we will not tolerate because of the potential for an innocent member of the public to be harmed.

“What I can say is this was a serious, brutal and callous attack and one that NSW Police will not stand for. We are 100 per cent committed to finding who was responsible and putting that person before the court.”