harrelson. o, the l al is to find xavior, find him safe and get him back. reporter: some 500 people, including volunteers, first responders and some of the 11-year-old s family members, joining the search sunday, east of des moines. volunteers traveling from miles away to help look for the boy. my youngest two are 4 and 6. and it s so close to home. it makes it hard. and i can t imagine what his parents are going through. reporter: temperatures dipping into the 40s each night since he went missing. harrelson, who is about 4 8 , was last seen near his home last thursday morning wearing a red t-shirt, blue pajama pants and black high top shoes. his birthday, just yesterday. and whit, authorities say they ve now shifted from ground searches to investigative work. at this point, there is nothing to indicate foul play but authorities say they have not ruled out anything just yet. whit? all right, alex, thank you. now, to that bombshell revelation from one of the