"I found out that Tyler, 8-year-old little Tyler, was hiding upstairs in a closet and the two killers, Charlie and Charles [Wade], took turns stabbing him to death," Caffey told "Nightline." "The hardest thing [was] to hear that. I remember when I heard that, I just couldn't believe that's how they did [it], and it goes back to that guilt and I felt I should have been able to save them and I couldn't."