When the state is the only entity with the investigatory powers plus corporate media and corporate control; the government can easily set that up with no problems.
Ray tried to recant his confession because of his fear of getting the death penalty. If police tell me that I need to confess to a crime that I did not commit, or face the death penalty; I might confess and hope I can prove my innocence later to get the death penalty off the table.
Ray later claimed a man he met in Montreal, Quebec, with the alias "Raoul" was involved and that the assassination was the result of a conspiracy. He spent the remainder of his life attempting, unsuccessfully, to withdraw his guilty plea and secure the trial he never had.
Allegations of conspiracy
Ray's lawyers maintained he was a scapegoat similar to the way that John F. Kennedy assassin Lee Harvey Oswald is seen by conspiracy theorists. One of the claims used to support this assertion is that Ray's confession was given under pressure, and he had been threatened with the death penalty. Ray was a thief and burglar, but he had no record of committing violent crimes with a weapon.
Those suspecting a conspiracy in the assassination point to the two successive ballistics tests which proved that a rifle similar to Ray's Remington Gamemaster had been the murder weapon, but did not prove that his specific rifle had been the one used. Moreover, witnesses surrounding King at the moment of his death say the shot came from another location, from behind thick shrubbery near the rooming house—which had been cut away in the days following the assassination—and not from the rooming house window.