The family of a man who went missing 24 years ago say a $500,000 reward for information is their "last roll of the dice" to find out what happened.
Marc Kristian Mietus was 21 when he moved from Melbourne to Queensland to start a new life in January 2000.
Weeks after arriving, he vanished.
It is believed he was murdered but a body has never been found.
"Twenty-four years of not knowing anything is really an emotional stretch for a family," Mr Mietus' father Kris said at a press conference on Friday.
"There must be someone out there who knows something."
Police on Friday announced they had doubled the reward for information about Mr Mietus' suspected murder to $500,000.
"We would like the people responsible brought to justice. We know we'll never get him back and get over the hurt and grieving," Kris Mietus said.
"This is our last roll of the dice."
Mr Mietus drove from Melbourne to Queensland in 2000, picking up a hitchhiker in NSW along the way.
The hitchhiker offered Mr Mietus a place to stay in Booyal, in Queensland's Bundaberg region.
They travelled to Booyal where Mr Mietus lived in a caravan until his disappearance.
A week before Mr Mietus disappeared he called his dad asking for fuel money while at a Gympie petrol station with an unknown passenger.
It was the last time his family had contact with him.
Mr Mietus was last seen alive at his Booyal residence on January 26, 2000.
Earlier that day Mr Mietus had been asked to pay his rent and said he would call a friend for money.
He rode his motorbike to a Booyal roadhouse and made three calls to a person known to police in Brisbane before returning to his property.
Police believe Mr Mietus was then picked up in a tan-coloured Ford sedan with an unknown number of occupants.
He has not been seen since.
It is alleged Mr Mietus was involved in the use and production of drugs at the time.
Police have launched a new investigation into Mr Mietus' suspected murder and plan to search the Booyal property on Saturday.
Police are also reinterviewing all witnesses.
Detective Senior Sergeant Tara Kentwell said on Friday anyone with information should come forward to provide the family with long-awaited answers.
"We do believe with public assistance, irrespective of the passage of time, this crime can be solved and offenders can be brought to justice," she said.
