Three men were arrested, including a 68-year-old man who police allege was using his position as a rental property manager to mask his involvement in several crop houses across the north-western suburbs.
He was charged with cultivating and trafficking a commercial quantity of cannabis and obtaining financial advantage by deception.
A 22-year-old man and a 25-year-old man from Roxburgh Park were also arrested and charged with trafficking a commercial quantity of methylamphetamine.
The 22-year-old and 68-year-old were due to face the Melbourne Magistrates Court on Tuesday night, while the 25-year-old was remanded in custody to appear at Port Macquarie Court on July 22.
The arrests come after two men – a 22-year-old Roxburgh Park man and 23-year-old Meadow Heights man – were charged on July 13 in relation to the same investigation.
During earlier raids in Roxburgh Park, Craigieburn, Glenroy, Meadow Heights and Reservoir, police found three stolen firearms, methylamphetamine, cocaine, ecstasy and over 100 plants believed to be cannabis, which were allegedly being grown across two residential premises.
They also found $21,000 in cash, suspected to be the proceeds of crime.
The two men arrested on July 13 were charged with cultivating a commercial quantity of a narcotic plant and possessing a traffickable quantity of unregistered firearms.