Anthony Thomas O'Grady, 52, was found at Thomas Armstrong Oval last Wednesday by an early-morning dog walker.

A crime scene was established at the park and on Ash Island, where a car, believed to be linked to the murder, was found.

Newcastle police have launched Strike Force Harrogate to investigate Mr O'Grady's death.

Detectives on the case have refused to comment on the cause of death or rumours that the murder was sexually or financially motivated.

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