Jason Guise was last seen on April 21, 2019 when he visited a food truck before returning to his home in the southeast Brisbane suburb of Wynnum.

He was reported missing on May 2 by his roommate and his body found six days later in a pit in a sewage treatment plant at Wynnum.

Workers were doing a routine check of a tank at the sewage pump station when they found the remains.

The well was under lock and key, and ringed by a 2.4 metre fence.

Police say a medical examination revealed Mr Guise died shortly after his last confirmed sighting when he rode a bicycle past Wynnum's Waterloo Hotel about 7.20pm on April 21.

Officers believe he received a food package from a van for the homeless but returned home and died somewhere other than the sewer.

A pre-inquest hearing is scheduled to be held before coroner Donald MacKenzie in Brisbane on August 17.

It is expected to consider when, where and how Mr Guise died and what caused his death.

Police in February announced a $250,000 reward to help solve the suspicious death.

Acting Detective Inspector Mark Mooney said at the time more than one person was suspected to have been involved in killing Mr Guise and moving his body.

"We encourage anyone who has information and for whatever reason has remained silent, to put that aside and come forward and speak with us, however insignificant they feel that information might be," he added.

A date for the inquest has not yet been set.

Australian Associated Press