The court was told that Samson Bazi, 31, was one of several gang members who attempted to extort $130,000 from the man, who was later bashed and told the so-called debt had been raised to $300,000.

Mr Bazi, a Comanchero, is currently charged over the alleged blackmail following raids by Victoria Police's anti-bikie Echo taskforce in May last year.

Most Melburnians are oblivious to the ruthless tactics of the underworld but bars and nightclubs are particularly vulnerable to standover rackets and the demands for "other rent" because of their dependence on cash and association with the illicit drug use.

In the wake of the fatal drive-by shooting outside Prahran's Love Machine nightclub last weekend, detectives continue to examine a potential link between the brazen attack and recent extortion attempts by at least two bikie gangs.

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Police are also investigating the possibility that a young man refused entry on the night could have returned with associates to exact revenge.

Security guard Aaron Khalid Osmani, 37, and patron Richard Arow, 28, were blasted with what is believed to have been an assault rifle as they stood outside the venue early last Sunday morning.

Mr Osmani died and Mr Arow is in a critical condition in hospital after receiving life-threatening injuries.

In the months preceding the horrific attack, members of the Comancheros and Finks had demanded payment from the club's owners, who also own the nearby Lux nightclub on Chapel Street.

The Age has been told that gang members have repeatedly threatened the venues, which prompted a recent change in security guards at Lux nightclub.

On one occasion, that is unrelated to the Love Machine nightclub shooting, Comanchero enforcer Emir Jaha menaced staff and patrons at Lux.

Jaha had only recently been released from prison after being convicted with another Comanchero member of intimidating a bankrupt property developer to pay an $850,000 debt, including taping bullets to the man's front door.

When handing down a 22-month sentence to Jaha, Judge Paul Lacava said: "A society where the physically strong stand over lesser persons will not be tolerated."

The template for extortion is brutally simple, but it has long provided a lucrative business model for outlaw motorcycle gangs and organised crime syndicates, including the Mafia.

Extortion is a notoriously difficult crime to investigate and prosecute. Most victims are deeply traumatised and are often reluctant to make a statement to police or testify in court.

Last year, former male model Hasan Topal, who became the temporary leader of Victoria's Comanchero outlaw motorcycle gang, was linked to a vicious assault and extortion attempt against a nightclub promoter.

But, while aware of the incident, Victoria Police's anti-bikie Echo taskforce was unable to persuade anyone to make a statement.

Topal is understood to have demanded weekly payments of $2000 before stealing the promoter's blue Honda Accord on May 26, 2018. The Age was told the nightclub promoter was lured to a meeting near a milk bar in Delahey, where he was allegedly ambushed and assaulted.

Topal, who is currently serving a custodial sentence over a wild brawl at a Canberra strip club, has been linked to other standover rackets across Melbourne, including the seizure of a Mercedes C63 from a luxury car hire business that was recently placed into liquidation.

Assault rifles were also used by Comanchero members to pepper South Melbourne strip club Kitten during a vicious battle for control of the security firm used at the venues.

The Cecil Street club was the subject of three drive-by shootings over an 18-month period, while former Comanchero treasurer Mark Ahern, 35, was handed a four year prison sentence over an arson attack on another Kittens venue in Caulfield South in February 2016.

The gang were also suspected of ordering the shooting of security industry figure Clay Auimatagi, who had previously worked at Kittens.

The violent two-year feud was finally resolved when Kittens owner Jason Dimozantos made a secret payment of more than $250,000 to the gang. In Melbourne's underworld, it appears a bundle of cash can settle even the most bitter of disputes.

Police have never made an arrest for the fire bombings of St Kilda venue Republica, which was the subject of two arson attacks within a month in 2014.

Bikies were again believed to be responsible for the blaze, which came after the restaurant instituted a "no colours" policy to deal with bikie gang members who were frequenting the venue.

Some of Melbourne's restaurateurs are also familiar with the veiled threats of standover men.

In 2013, the three outlets of the Woodstock pizza chain in Brunswick East, Fitzroy North and Essendon were peppered with bullets in a triple shooting on October 30, 2013.

The Essendon outlet was shot up again a few months later, while a former Woodstock manager was badly assaulted. No report was made to police and the shootings remain unsolved.

Police suspect members of the Calabrian mafia were responsible, another in a long line of "protection-style" exortortion rackets where being allowed to operate in specific area or industry comes at a steep price.

In some cases, restauranteurs who refuse to pay – or pay late – have seen their homes burnt to the ground or family members threatened.

The reality is that the climate of fear means the message often gets received that paying up is simply part of the cost of doing business.