The first thing that needs to happen is Papadopoulos should file a motion in his criminal case seeking to have the judgment against him set aside, on the grounds that the prosecution failed to disclose this clearly exculpatory evidence against him, as they had the legal obligatuion to do. Once a judge makes the determination that the his conviction was tainted, the whole house of cards will start to collapse. See Senator Ted Stevens.
You must note that Senator Stevens was falsely convinced, and died before he was exonerated.