'Distinctive' car seat covers could lead authorities to Brisbane man's killer

Car seat covers found next to a murder victim in a disused septic tank in Brisbane may lead authorities to his killer, detectives have announced.

Wayne James Youngkin's remains were found in the tank on a property at Brighton, northeast of the CBD, on November 29 - 30 years after he went missing in 1986.

Two distinctive, striped car seat covers may hold vital information about Youngkin's murderer, Acting Detective Superintendent Mick O'Dowd said.

Investigators said they hope to speak to two people who contacted them in December with "very specific" information regarding the case.

Acting Det Supt O'Dowd said someone had rung Crime Stoppers on December 1, and a letter had been received at Sandgate Police Station on December 9.

Authorities previously said a male caller, who rang Sandgate Police Station in August 1992, might hold evidence that will help them solve the case.

Acting Det Supt O'Dowd said there was clearly a lot of knowledge in the community regarding Youngkin's disappearance.

"It seems that as time progresses some more people have been willing to just supply a little more information, which from our point of view is very positive," he said.

Youngkin was 29 or 30 when he went missing.

His last known activity was making a passport application in 1986 while he was living with his grandmother and uncle at the Brighton home.

His grandmother and uncle have both since died.

A plumber found Youngkin's remains while working at the property, which was not searched at the time he vanished.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.