the boys spent the evening playing video games and listening to music in randy and kate's basement. >> i went down 10:30 or so that night and told them maybe crank the music volume down a little bit. >> reporter: but around midnight, diren was bored, restless and suggested he and robby take a walk. >> and i was kind of, "i'm just really tired, diren." he was like, "come on." and i was like, "okay." >> reporter: so while kate and randy slept upstairs, robby and diren slipped out the back door for a walk around the neighborhood. they headed up the nearby hill and then turned on to deer canyon road. then, robby says diren suddenly walked off in a different direction, and robby lost sight of him. >> i was like, he's not coming. i'll continue walking. >> reporter: robby says he called out to diren, but there was no answer, so he kept