was no answer, so he kept walking, figuring diren would catch up. >> that is when, like, i heard someone yelling. "you're there. i see you there." something like that. after that just the shots, like, three or four shots. and i just started running. >> reporter: gunshots in a quiet residential neighborhood. a now-terrified robby ran back home. >> he was faster than i am. i said, he's probably coming. i was almost sure that he was coming. >> reporter: but diren wouldn't return. and what happened to the german exchange student would simultaneously make headlines around the world and get americans asking, how far can you go to protect your home and family? coming up -- >> 911. what are you reporting? >> a robbery. >> an urgent call to 911. >> somebody entered into our garage. shots were fired. you've been taking mental health meds, and your mind is finally in a better place.