>> dylan lange is the son of byron's friends, john and kathy. >> in little falls. you know, your regular, high school crowds. like, the jocks and the goth kids. then, you have a group that is misguided. >> dylan didn't know haile well, but says, at school, nick was no angel. >> what did you know act those about those two teenagers? >> i knew that nick was aggressive. he would be the kid, who would push up against the locker. >> kind of a bully? >> right. he was a bully. >> and as it turned out, a thief. after the shootings, authorities determined nick had been behind one of those previous burglaries at byron's house. just a month earlier, he and a friend broke through this door and stole thousands of dollars in cash and priceless-family heirlooms. and more disturbingly, two guns.