only 3 years old when his mom left the house, never to be seen or heard from again. police soon learned that aaron may have witnessed the unspeakable, the murder of his own mother. the boy would become a man before the whole truth was revealed. and though memories faded, the evidence pointing to the killer couldn't stay buried. here's dennis murphy with "she never left. " >> she'd been gone from his life, unaccounted for, for more than 20 years. his mother, bonnie. >> it was odd to be the one that found her. >> because you'd spent a lot of your life looking for her, right? >> yes, sir. >> there's a poignant video of the mother and child's last christmas morning together. december 1992. the boy, aaron, was 3 1/2.