Police are searching for the body of Adelaide man Kerry Giakoumis as part of the investigation into his suspicious disappearance.
Search and rescue crews, as well as divers, are in the Jackson Creek area in the Melbourne suburb of Diggers Rest after information was provided to police.
Mr Giakoumis' body is yet to be located.
The 29-year-old man was last seen at the Hells Angels clubhouse on Lipton Drive, Thomastown in the early hours of Wednesday, June 10, 2020.
Detective Superintendent Paul O'Halloran said Mr Giakoumis' disappearance had been a "significant" case over the last 14 months.
"We've created a taskforce involving specialist detectives with experience in the investigation of missing persons, murder and outlaw motorcycle gangs because we believe this gives us the best opportunity to solve this case," Mr O'Halloran said.
"We are committed to following up every avenue of enquiry and holding those with any level of culpability in relation to Kerry's suspected death responsible.
"Police have believed for some time that he has met with foul play and all the information we have received, particularly over the past few months, just confirms that.
"We have information that his body may potentially have been dumped in Jacksons Creek near Diggers Rest and we've had our Search and Rescue police, along with specialist divers, out there meticulously looking for any trace of Kerry."
Mr O'Halloran appealed for anyone with information to come forward.
"I would also stress that this can be done anonymously," he said.
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Mr Giakoumis had travelled from Adelaide to Melbourne on June 5, 2020, and had told his family that he intended to work here as a concreter.
Police said it is understood that Mr Giakoumis was not a patched member of the Hells Angels Outlaw Motorcycle Gang.
While in Melbourne, Mr Giakoumis regularly spoke to his family in South Australia and his mum had booked a flight home for Wednesday, June 10, 2020.
When he did not board his flight, he was reported missing to police.
Detectives are particularly interested in speaking to anyone who has information about what happened at the clubhouse or any other location in the early hours of June 10.
They would also like to hear from anyone who noticed any suspicious activity in the Jackson's Creek area around the time Kerry went missing.
Police have released a new image of a man they believe could help with their enquiries.
This man was seen in a group of men who were in company with Kerry on the night of his disappearance.
Anyone with information about Kerry's disappearance is urged to call Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au.