Queensland Police are offering $500,000 for information on a cold case murder of a hitchhiker in the state's north after new details came to light.
Anthony "Tony" Jones was last seen in Hughenden, a small town west of Townsville, on November 12 in 1982.
He planned to hitchhike to Mt Isa to meet his brother but never arrived and has not been heard from since.
"In 2002, the Coroner ruled that Anthony Jones was deceased and had died at the hands of a person or persons unknown," Queensland Police said.
"Investigators believe Tony has been murdered."
Fresh evidence in the case suggests Jones was involved in a fight at the Grand Hotel in Hughenden on the evening of November 12.
"On 19 January 1983 police received a handwritten letter under the name 'Lochiel' postmarked from Cairns, indicating Tony may have been buried in the Fullerton River," police said.
"The following day an extensive search of the area commenced and was cleared without any items of interest being located.
"Over the following years, police investigations included approximately 60 statements and 270 inquiries completed by investigators.
"A number of persons of interest have been investigated, and numerous land-based searches conducted in areas including the Fullerton River, Cloncurry River and Hughenden Slaughter yards."
Detectives said Jones was carrying a Voerre .22 calibre rifle with serial number 257435, a large blue backpack with aluminum framing and a green sleeping bag, a green one-man tent, along with various personal items such as toiletries at the time.
None of those items have been recovered.
Over the years the reward has incrementally increased and now sits at $500,000, double what it was previously.
Detectives will question people in Hughenden this weekend.
Detective Sergeant Brenden Stevenson said he believed loyalties might have changed over the last 40 years.
"We are also urging anyone with any information as to the whereabouts of Tony's rifle, or the identity of the person who posted police the letter from Cairns in 1983, to please contact police."
