Nick Falos, then aged 55, was last seen on March 14 in 2003 about 8.30am as he drove his red Porsche along Albion Street in Brunswick.
His Porsche coupe with registration JD 944 was later found burnt out in the Yarra State Forest at the intersection of Mt Beenak Road and Torbetts Road, near Gladysdale, three days later.
A concerned neighbour reported the Thornbury man missing on April 1 after not seeing him for several weeks.
Mr Falos also drove a brown 1975 Holden sedan which was found parked at his home.
Police undertook an extensive search through bushland near Gladysdale on May 16 in 2003 but were unable to find him.
Detectives from the Missing Persons Squad are treating the man’s disappearance as suspicious and believe he has been murdered.
Investigators believe a phone call was made from a payphone to Mr Falos on the morning of March 15, 2003.
Police are probing whether cannabis cultivation in the Yarra State Park and Yarra Junction areas is connected to his disappearance after receiving information from a number of sources around the time Mr Falos went missing.
Detective Acting Inspector Tony Combridge said while police believe Nick was killed, they were still searching for answers.
“It may be 18 years since Nick disappeared, however I would like to strongly reinforce to the community that this is very much an active investigation,” he said.
“While Nick is no longer believed to be alive, we are still hopeful of finding out what happened to him.
“It is also our belief that a number of people were potentially involved in Nick’s murder.”
Detective Acting Inspector Combridge said police believe there are multiple people out there who could assist with the investigation.
Police are keen to speak to anyone who recalls seeing Mr Falos or his red Porsche in the Yarra Junction area on March 15 or 16 in 2003.
“There is the possibility that the person or persons responsible for his death may have spoken to someone about Nick and today’s reward announcement may lead to them finally coming forward with information,” Mr Combridge said.
“People’s circumstances can change over the years and someone who may not have wanted to provide information to police previously may now feel ready to do so.”
Police arrested a 77-year-old Endeavour Hills man in relation to Mr Falos’ disappearance on August 17, 2018.
An 84-year-old man from Devon Meadows was also arrested on August 14 in the same year.
However, they were both released without charge.
Mr Falos is of Greek heritage and also goes by the name Nikolaos Falieros.
Investigators have released photos of Mr Falos and a vehicle similar to his Porsche in the hope that someone will remember seeing him or the car.
A reward of up to $1 million will be paid at the discretion of the Chief Commissioner of Police for information leading to the apprehension and subsequent conviction of the person or persons responsible for Mr Falos’ death.
The Director of Public Prosecutions may also consider granting indemnification from prosecution to anyone who provides information as to the identity of the principal offender or offenders involved.
“It doesn’t matter how insignificant you think the piece of information is, it could be exactly what our investigators need to make a breakthrough in this case,” Mr Combridge said.