When Inspector Bruce Knight had initially mobilised his Special Operations Group colleagues to respond to the explosion in Russell Street, all members assisted. However, at 4pm that day, he had to deploy a team to respond to a bank robbery in Donvale. The get-away vehicle used in the robbery was a stolen Holden Brock Commodore Special. The SOG members arrived too late, and the Commodore was nowhere to be found.
Detectives from the Armed Robbery Squad had asked members of the Stolen Motor Vehicle Squad for a list of any stolen silver Brock Commodores that might be the car from the Donvale heist. One such vehicle was fished out of the Yarra River near Wonga Park on 7 April.
On Monday 14 April, Detective Sergeant Arthur Adams from the Stolen Motor Vehicle Squad arrived at the Port Melbourne compound to examine the Brock Commodore. The car was in the process of being transported to the Stolen Motor Vehicle Squad's compound which also housed the bomb car. While he waited for it to arrive, Detective Adams, and fellow detectives, John Bradbury and Steve Quinsee looked over the bomb car and noticed the caterpillar of holes where the chassis number had been drilled out. Like the investigators who had examined it before them, they too though the drilling out of the number was unusual. Bradbury and Quinsee had never seen numbers removed like that before, and Adams had only seen it once - a decade earlier. And like their colleagues, their observations were purely academic - until the stolen Brock Commodore was delivered. To the amazement of the three detectives, the Brock Commodore had its serial numbers drilled out in exactly the same way as the bomb car. Arthur Adams immediately alerted the Taskforce and met with Bernie Rankin and Daryl Clarke.
'If I were a betting man,' Adams said, 'I would say these two cars were connected.'
Could this be a coincidence? A Commodore explodes in Russell Street at 1.01pm and three hours later, another Commodore with the same drill markings is involved in a bank robbery in Donvale at the exact time when all available police resources were tied up in the city.
The three Stolen Motor Vehicle Squad detectives were able to provide another connection. Three weeks before the bombing a stolen red Daimler car was pursued by traffic police along the Calder Highway in East Keilor. The car crashed and the driver escaped. Shortly after, the driver stole another car at gunpoint. He was dangerous and the police were anxious to catch him.
In the boot of the crashed Daimler was a bag containing cut up pieces of car number plates. The car was reported as stolen and detectives from the Stolen Motor Vehicles Squad were called in. Putting the pieces together, investigating police found plates from the stolen Brock Commodore Special - CCH 997. Detective John Bradbury made a note in the police data base that if the Brock Commodore was found, he wanted be notified immediately.
When forensically examined, the holes drilled into the chassis number in the Brock Commodore were 8mm in diameter - the same size as those drilled in the bomb car. The VIN plates as well as the compliance plates had also been removed using the same method as the bomb car - while some of the pop rivets were still in place, the plates had been torn off. As with the bomb car, the engine number hadn't been touched.
Clarke and Rankin discussed this new development. They couldn't ignore Crupi as their strongest suspect, but at the same time, they needed to explore this new lead. Clarke put a small team of detectives to follow up the Brock Commodore link.