A former Victorian police officer who allegedly became a trusted member of a criminal syndicate that traded in drugs and guns has been charged with several offences, including commercial trafficking.

David Lister was allegedly found carrying half a kilogram of ice at an airport within months of resigning from the force. Mr Lister was a senior constable based in the northern suburbs before he was allegedly recruited by the syndicate that supplied ice to Melbourne's north west, central Victoria and the Queensland city of Townsville. Police say he resigned from the force in January.

North West Regional Crime Squad detectives say they have dismantled the cartel, which is linked to shootings and cannabis crop run-throughs in Melbourne's western suburbs, after a series of warrants on Monday and the charging of eight alleged key syndicate members, including its suspected ringleader.

Mr Lister, aged in his 30s, faced a court in Townsville last month after he was arrested on April 3 at the airport allegedly carrying half a kilogram of ice – about half a million dollars' worth – in a backpack.

He was bailed back to Melbourne and on Monday was charged with Victorian offences including commercial trafficking and misconduct in a public office following raids in Melbourne, country Victoria and Queensland.

The raids – in Essendon, Airport West, Kurunjang, Maribyrnong, Caroline Springs, Braybrook, Altona, St Albans, Kings Park, Corop (near Rochester) and Townsville – were the culmination of a seven-month investigation by the crime squad that allegedly uncovered the following:

• Sixteen guns including a military grade Theron sub-machinegun, believed to be only one of two found by Victorian police. It was recovered at a house in Rockbank in January.
• 1.5 kilograms of ice, equivalent to more than a million dollars' worth.
• Two clandestine laboratories, a heroin press and a cannabis crop house that was allegedly at the home of the former officer.
• Fluoroamphetamine​, a rare illegal stimulant, in a bathtub at the Rockbank unit three associates frequented.

The syndicate was initially identified after the crime squad linked it to a wave of dangerous aggravated burglaries, also called run-throughs, that targeted cannabis grow houses in the city's western suburbs last year.

Assistant Commissioner Stephen Leane said criminals were using heat-seeking technology – including a device stolen from a fire station – to locate the houses where cannabis was being grown so they could steal the drug.

A murder and several assaults were linked to the gangs.

"There were several groups but we were able to target and isolate one of those," Mr Leane said.

Crime squad Detective Senior Sergeant Jeff Cocks said more than 20 people connected with the syndicate have been arrested since the investigation began, but the police focus has been on charging key members.

"To us the ultimate goal is not only charging people, it's dismantling the syndicate and doing so by using the old Al Capone method; if you can rip out their assets and finances – restrain houses, take cars – that has a massive effect," Senior Sergeant Cocks said.

Among those arrested on Monday was alleged ringleader Jarrod Hennig, a 32-year-old originally from Melton, who was charged with trafficking a commercial quantity of ice and was remanded after facing the Melbourne Magistrates Court on Monday afternoon.

Mr Hennig ran building company Trades Group, where both Mr Lister and another alleged syndicate member, Luke Debono, worked.

The Melbourne Magistrates Court heard last month that Mr Debono had previously been investigated by armed crime detectives over a non-fatal shooting in Maidstone last year that an associate, who told investigators he was "taking one for the boys", was later charged and convicted of.

Mr Debono was arrested in January after he was seen frequenting the Rockbank unit where the sub-machinegun was found.

It is believed the 21-year-old is one of the first in the state to be charged under Victoria's new firearm trafficking legislation passed by Parliament late last year.

Senior Sergeant Cocks said the alleged syndicate leaders knew each other through the outer north-western suburb of Melton.

"The Melton connection is a strong connection, it might go back 10 or 15 years ... They trust each other so it makes it harder to infiltrate," he said.

It is believed Mr Lister had known Mr Hennig before he joined the police force through connections in Melton.

Mr Leane said police would keep an "open mind" as to whether the former officer had used his position of power to assist the syndicate.

"We're not alleging any of that at this stage. We will keep an open mind in the long-term," Mr Leane said.

He said Professional Standards Command investigated and suspended Mr Lister for drug use when he was still in the force late last year. He resigned mid-January this year.

Mr Leane said the Regional Crime Squad's investigation was an example of the unit, which was formed last year, dismantling organised crime.

"They're people that might live next door to you ... but they're prepared to use violence, they were prepared to use firearms, they had a lot of cash, and as we've seen they've dragged a former police officer into their network really quickly," he said.