North Queensland police say they may now know where hitchhiker Tony Jones was murdered more than 30 years ago.
Mr Jones, who was 20 when he disappeared, last made contact with his Perth-based family on November 3, 1982, to say he planned to hitchhike to Mount Isa from Townsville.
He was reported missing about a week later and has not been seen since.
Several recent tip-offs to Crime Stoppers have led police to believe Mr Jones may have been murdered on his way to Mount Isa in the small town on Hughenden, inland from Townsville.
Officers are now appealing for those who called the anonymous police line to come forward.
Lead investigator, Townsville Detective Acting Superintendent Cheryl Scanlon, says they could hold the key to a major breakthrough in the case.
"Several of those callers have provided information that leads us to suspect Tony Jones was murdered in Hughenden," she told AAP.
"I'm appealing to these to people to again make contact with Crime Stoppers and identify yourselves if you feel that you can.
"Your information is extremely important to the investigation."
Supt Scanlon, who wouldn't reveal what new information had come to light, says it is rare for police to ask anonymous callers to come forward.
A team of detectives will spend this week in Hughenden trying to track down people who lived and worked in the town the year Mr Jones disappeared.
Previous investigations had focused on Townsville and a campsite at Cloncurry River.
The high-profile case sparked National Missing Persons Week, which last year marked its 25th year.
A coronial inquest in 2002 could only conclude Mr Jone's death was "at the hand of a person or persons unknown" and police investigations should continue.
At the request of the Jones family the state Attorney-General agreed to reopen the inquest in 2010 but no date has been set for the hearing.