Drug dealers key to Qld man's death

Queensland police believe a couch surfer who fell in with "mid-level drug dealers" was killed on the day he was last seen two-and-a-half years ago.

Sam Robert Price-Purcell, better known as Sam Price, disappeared on February 16, 2015.

There has been no contact with family and friends, or use of social media and bank accounts since that date.

Homicide Group Detective Inspector Damien Hansen on Friday appealed for anyone with information about what happened to the 25-year-old to come forward.

Mr Price was last seen in several locations on Brisbane's northside, between Mitchelton and Fortitude Valley.

Insp Hansen said he came from a good family but had "gone off the rails" and lost contact with them, which resulted in his disappearance taking some time to report to police.

It became a homicide investigation about two months ago.

Investigators had received "several versions" from his associates about what they thought happened to him.

"My belief is he died on the 16th," Insp Hansen said.

"There's no sign of life after that."

Police are now trying to work out what parts of those versions are true.

Mr Price was known to police and his associates were "mid-level drug dealers", Insp Hansen said.

He urged anyone within the 25-year-old's network to come forward, and said there were resources like witness protection available to them.