there is so much evil in the world. the murder of his mom was enough. but to take the little boy with her, it s incredible. reporter: flowers and pictures line the memorial where police found his body in clarks burg, along with messages and personal footballs from classmates. william was the most beautiful, wonderful, cheerful child in the entire world. entire world. and there is no reason this should have ever happened to him. reporter: william s stepfather, curtis lopez, is believed to have murdered him. police believe he stabbed his mom to death and then plotted to kill the little boy. reporter: at this gas station, near where the body was dumped. it shows a playful william, smiling as does another video of the two at a storage unit. just minutes after it was captured, he could would be dead, and it would take 17 days for authorities to find his body. we just play prayed just prayed a lot. and it s hard. reporter: just days before the murder, a friend claim