Four CFMEU vehicles were seized during Monday’s sweep of raids linked to the union’s activities, which included a search warrant at its CBD headquarters.

Also confiscated in the operation were 10 mobile phones, a schedule four poison, laptops, documents, iPads and USB storage devices.

Detectives arrived at the Elizabeth St site in Carlton around 9.30am Monday and were seen exiting the building just before noon.

Victoria Police said detectives from Taskforce Hawk executed warrants at six addresses across Melbourne on Monday morning as part of its ongoing investigation into information provided about secret commissionsallegedly offered to CFMEU officials by former Mongols bikie Tyrone Bell.

Bell began an industrial relations consultancy after losing his position with the CFMEU as a delegate.

Taskforce Hawk has been investigating whether organisers leaked information to Bell to advance his industrial relations business.

“This is a shake the tree sort of thing to see what comes out,” a source said.

Warrants were carried out at Chirnside Park, Westbury, Gisborne, Powelltown and Somerville.

A .22 rifle and ammunition which were allegedly not being stored properly were seized at Westbury.

“The investigation relates to allegations of drug trafficking as well as secret commissions,” a Victoria Police statement said.

Five men were arrested in the raids, including a 36-year-old from Chirnside Park, a 46-year-old from Westbury, a 27-year-old from Gisborne, a 56-year-old from Powelltown and a 37-year-old from Somerville.

The Chirnside Park man was charged with possession of a schedule four drug and the Westbury man faces firearms charges.

Detective acting Superintendent Jamie Walker of the organised crime division said corruption, intimidation and violence within the construction sector was unacceptable.

“We will continue to target serious and organised crime entities and dismantle corrupt and criminal business activities in the construction industry,” Supt Walker said.

Taskforce Hawk is the specialist unit probing rogue conduct within the construction industry.

The CFMEU confirmed it had been raided.

“CFMEU has been made aware of a police operation this morning as part of Taskforce Hawk,” it said in a statement.

“As this is a live police matter, CFMEU cannot comment further at this time.”

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