A MISSING gun has been revealed as the latest clue in the 31-year Wayne Youngkin murder mystery.

Mr Youngkin, from Brighton in Brisbane's north, vanished in November 1986. He was not reported missing until 1992.

His remains were found at the bottom of his disused septic tank on North Rd, Brighton, last November, sparking a renewed hunt for his killer.

Yesterday, the next chapter in what is now the largest active murder investigation in Brisbane led police to swamplands at Sandgate, 20km northeast of Brisbane's CBD.
 

Detective Inspector Tim Trezise said that police had received a tip-off in recent weeks about a lagoon at Deagon Wetlands potentially containing key evidence, disposed of following Mr Youngkin's killing.

Divers were told yesterday to be on the lookout for a gun on the lagoon floor.

But a six-hour search by the police dive unit and ­Defence divers failed to find any evidence.

Mr Youngkin is described by police as "well-known" in the Brighton area.

He was reported missing in 1992 by his grandmother and uncle, with whom he had been living six years earlier.

Both are now dead, which has caused problems for investigating officers in recent decades.