>> it never occurred to me that it would be anything like this. and he said -- then he told me we don't know, we just found him. i said what? what do you mean? i said did somebody kill him? and he looked at me and -- we don't know, keith, i can't tell you anything. >> keith bjerk last saw his son just the night before, june 10th, 2012. it was 11:00 at night. >> he was going to run out to a gas station. he said i'll be right back. i said okay, i'll see you in the morning, son. and i gave him a hug and kiss good night. and i was watching tv on the couch. he picked me up and shook me like that, said love you, dad, i'll be right back. >> his parents would later learn that at the gas station christian ran into a friend and ended up going to a house party. his body would be found a short distance away. what killed this healthy 18-year-old was a mystery that was about to strike this small midwest community again.