Delton Dowthitt, 16, had dropped out of ninth grade that spring and moved out of his mother's home in Oak Ridge North. Dennis Dowthitt, 45, ran a shabby used car lot in nearby Humble. By contrast, Gracie Purnhagen, 16, and sister Tiffany, 9, came from a stable home. At about 8:45 p.m., Dennis Dowthitt's white pickup truck cruised into the bowling alley parking lot and witnesses saw the Purnhagen girls get in. Dennis Dowthitt slid out of the truck and said, "I messed up." Delton and young Tiffany stood watching as Dennis Dowthitt pummeled Gracie to the ground, unsheathed his buck knife and cut her throat. Delton wrapped his mitts around the girl's neck and squeezed until she fell unconscious.