The question of who murdered a Fayetteville, North Carolina military wife and two of her young daughters in their own home, leaving only one toddler alive, seemed to be answered with the conviction of a soldier who was a husband and a father himself. But years later that verdict was overturned and the original suspect, Tim Hennis, was acquitted. Then, after two decades of freedom, dramatic new evidence points back to Hennis. Elizabeth Vargas reports on a murder mystery that played out over 25 years... and came to a surprise ending in a North Carolina courtroom this past April.