Wee Johnnie Norrie

Wee Johnnie Norrie is the fourth book in the Dave Harris Murder Mystery Series. Harris is called upon to solve the murder of a man whose body was found in his apartment two years after his death.
Just identifying the victim was going to be a major problem. Why did the victim lie unnoticed by anyone for so long?
Who killed him and why? And just who wanted John Norrie dead? Was it a conspiracy?