Why are wrongly-convicted people still imprisoned in Missouri?
"48 Hours" correspondent Erin Moriarty talks with two Missouri men, Kevin Strickland and Lamar Johnson, who have served a combined 70 years in prison for murders most people now believe they did not commit. And yet, even though prosecutors have called for their release, innocence may not be enough to earn them their freedom – both men are still behind bars. So, what's going on in the state of Missouri?