Solving Unsolved Mysteries JonBenet, Jimmy Hoffa

Some murder cases that gains notoriety seem to be buried for ever as unsolved mysteries take for example the cases of JonBenet Ramsey and Jimmy Hoffa. There may be no closure for ever of who were the killers? In the case of the labor union boss Jimmy Hoffa the body was never found. What is needed is a promise of amnesty or reduced charges for who ever come over and confess or provide damning fool proof knowledge of their stories . A variation can be made in term of time capsule which can be opened only after the confessor or probable killer death.
The congress or the department of justice can come forward and offer a deal for the killers under promise of amnesty or minimal sentences.
This lovely six years old JonBenet suffered a horrible death and we are entitled to know what happened! Similarly Jimmy Hoffa was very important shadowy man and his death was very intriguing.
Unresolved murders that gained large national attention should be resolved one way or another even under promise of amnesty undoubtedly after all leads have been exhausted and after sufficient lapse of time for the JonBenet case more than ten years have passed.