Police investigating a 20-year-old cold case where a “road gang” robbed an armoured van on a Melbourne freeway have searched a Queensland property.

The key to a 20-year-old Melbourne armoured van robbery where brazen thieves made off with $4 million may lie on the other side of the country.

Police investigating the “road gang” heist have searched a rural property in far north Queensland where they collected items for forensic testing.

Detectives from Victoria’s Purana task force, which targets organised crime, also believe a distinctive vehicle may have been driven to Queensland after it was used in the hold-up.

Thieves posed as a fake roadworks crew, complete with signs and witches’ hats, so they could pull over an unsuspecting Armaguard truck on before robbing it at gunpoint.

Up to five people are sought over the robbery, in which four people posing as road workers stopped the Armaguard van on a Monash Freeway ramp at Richmond on June 22, 1994. They escaped in two getaway cars with $4 million.

Queensland police on Tuesday said Purana detectives had found links with a rural property at Mossman, near Port Douglas, as well as a ute believed to have been used be used in the armed robbery.

Police searched the Mossman property and other nearby locations in mid-March, seizing a number of items which have been sent to Victoria for testing.

Police say one or more of the thieves appear to have travelled to Queensland after the robbery.

Their ute – an early model Dodge or Bedford with metal storage lockers on each side of the tray – may have been sold to a local after it was dumped at a North Cairns wreckers.

The current owners of the Mossman property have been ruled out as suspects.

Purana detectives in March charged an unnamed Melbourne lawyer with allegedly attempting to launder some of the stolen cash.