There's a bit more to the Leon Chambers/Gable McDonald story . . . The involved LE agencies in Mississippi and Louisiana did not stop the investigation with McDonald's sworn confession; they thoroughly examined every aspect of McDonald's assertion to corroborate or refute each detail--to include an extensive search for the murder weapon, which was never found. Ultimately, McDonald's confession could neither be proved nor disproved; that was sufficient to instill reasonable doubt if introduced at trial. The prosecutor in Mississippi knew this, and exercised prosecutorial discretion not to pursue another trial. The question of perjury/false statements was examined in Louisiana, but it was determined to be an undesirable case to pursue.