How a Missouri law keeps wrongfully convicted inmates like Christopher Dunn behind bars
Christopher Dunn was convicted of a murder in Missouri three decades ago and remains behind bars, even though two witnesses have since admitted they lied at his trial. He’s still imprisoned due to a quirk in Missouri law: prisoners serving life sentences aren’t entitled to innocence claims in the same way that death row inmates are. CBS News and "48 Hours" correspondent Erin Moriarty explains.