Double Jeopardy Question?

A person was originally charged with murder, but made a deal with prosecutors in exchange for his testimony against a co-defendant. He was given a deal of accessory to a felony. He lied during investigation and again during the trial. The man he testified against was convicted of murder (he didn't do it). My question is this: if the man who was charged with accessory were to come forward and tell the truth about his co-defendant to get him out of prison, will he be able to be charged with murder again or would that be double jeopardy since he plead out?