Homicide detectives have appealed for dashcam and CCTV footage to help them find those responsible for the execution of Melbourne fruiterer Paul Virgona as he drove to work early Saturday morning.

Key points: Detectives have appealed for footage from several suburbs in Melbourne's east

Detectives have appealed for footage from several suburbs in Melbourne's east Police believe Mr Virgona's killers dumped two cars before fleeing into parkland at Bayswater

Police believe Mr Virgona's killers dumped two cars before fleeing into parkland at Bayswater The motive behind the killing remains unclear

Police now believe the people who gunned Mr Virgona down as he drove his white van out of Eastlink's Mullum Mullum tunnel in the city's east had been following him from the moment he left home.

Detective Inspector Tim Day said Mr Virgona, 46, left his Croydon home about 2:00am on Saturday, in keeping with his daily routine.

But on this morning, police believe he was followed from his house by a Mercedes-Benz C200 sedan with the registration plate AZE 110.

As Mr Virgona's city-bound van emerged from the tunnel at Donvale about 2:15am, he was shot dead in the driver's seat.

His white Volkswagen came to rest in the right-hand lanes of the tollway, sparking calls from other motorists about a car blocking lanes on the EastLink.

Mr Virgona was the only person inside his van when he was shot multiple times. ( ABC News )

Inspector Day said the Mercedes then exited the EastLink at Springvale Road before it was dumped, burnt out, in Jaxlee Court in Mooroolbark 20 minutes later.

Police believe two men then got into a grey Volkswagen Amarok ute with the numberplate 1MC 9PG.

That car was spotted and chased by police through Ferntree Gully before it was dumped next to the Marie Wallace Bayswater Park.

"They take off through the park, police lose them at that point in time," Inspector Day told ABC Radio Melbourne.

Police believe Mr Virgona's killers dumped a car at Bayswater before fleeing into the park. ( ABC News )

Appeal for CCTV, dashcam footage during critical window

Despite a search by police helicopters, dogs and the Critical Incident Response Team, police were unable to find the two men.

Inspector Day said police now needed help from anyone in the surrounding suburbs of Ferntree Gully, Croydon, Ringwood, Donvale, Mooroolbark, Wantirna, Bayswater and Boronia.

He said anyone with dashcam footage who was driving through those suburbs between 1:30am and 3:00am should check for the registration plates of the cars involved and call Crime Stoppers if they recognise them.

Numberplates of vehicles involved: ABE 158 — Mr Virgona's white Volkswagen wagon

ABE 158 — Mr Virgona's white Volkswagen wagon AZE 110 — The killers shot Mr Virgona from this Mercedes-Benz C200 sedan before it was dumped in Mooroolbark

AZE 110 — The killers shot Mr Virgona from this Mercedes-Benz C200 sedan before it was dumped in Mooroolbark 1MC 9PG — A grey Volkswagen Amarok ute which was dumped at Bayswater

The detective also urged residents in the area to check their CCTV systems for footage that may have captured the killers, particularly as they ran from their car and moved about the Bayswater parkland between 3:15am and 4:00am.

Police were continuing to search the parkland in Bayswater on Monday after extensive searches near the creek over the weekend.

Motive remains a mystery

Despite a flood of information, Inspector Day said police were still unsure why Mr Virgona was targeted or whether it was a case of mistaken identity.

"Paul's not known to police. We're still looking into what possible motive there might be," he said.

Police ran line searches at the Dandenong Creek in Bayswater parkland over the weekend. ( AAP: Julian Smith )

When asked whether there was a possibility that Mr Virgona was killed by criminals operating within the wholesale fruit and vegetable market, Inspector Day said it was "too early to tell".

"I agree that's one avenue of inquiry that we're looking at," he said.

On the weekend, police said Mr Virgona was known as a hard-working man who was dedicated to his family.

The ABC understands he worked at his family's business, Virgona's Fresh Produce, which is based in Thornbury and sells fruit and vegetables to restaurants and cafes.