In November 1989, Toowoomba teenager Annette Mason was killed in a savage attack.
Nobody has been charged over her murder and a 1991 coronial inquiry returned an open finding.
Inspector John Brand managed forensics before his retirement and continued retesting crime scene material, which he says has resulted in fresh information.
“We have significant information and that information involves forensic evidence and we now have additional forensic evidence that I believe will assist in solving this terrible murder,” he said.
Mr Brand said finding Ms Mason's killer should be made a bigger priority.
"I personally think that it needs to be given to a dedicated team of detectives, people who have the ability and commitment to solve this," he said.
"The significant evidence available since that inquest and some of it in very recent times, I think would greatly assist in bringing this terrible crime to a successful conclusion."
Queensland Police declined to be interviewed, but in a statement said the investigation remained open and urged anyone with new information to contact Crime Stoppers.
A reward of $250,000 has been set for new information.
The Mason family feel they have been denied justice and are urging the Queensland Government to hold a fresh coronial inquest.
Ms Mason's sister Linda is leading that campaign and said her family deserves answers.
"It's like a living hell," she told 7.30.
"You're just stuck in limbo."
"This young life has been taken but no one has been charged — no one's found responsible."
Another retired police officer, highly decorated Detective Brian Tighe, who led the investigation for 10 years, continues to be troubled by Ms Mason's murder.
Mr Tighe retired 15 years ago but continues to scour his notes for an additional clue.
"When you take an oath of service, you don't give it back when you retire, you continue to care, because its in your nature," he told 7.30.
"These people are suffering."