i know they did not get along on the trip. carl threatened to kill mr. murphy, half-heartedly. carl got suspended for that. >> he says his friend was never the same after that suspension. >> when carl came back, he was pretty angry. he felt like the suspension ruined his chances for getting into college and his future. >> reporter: classmates say carl was punished and could be combative. >> he would say, oh, i could shoot everyone up. >> obviously he wasn't kidding. >> no one thought he was capable of this. >> carl was a good guy. he made my days beter. that's what hurts the most, he wasn't a villain. >> reporter: today's disbelief, tomorrow's determination. >> i want to see arapahoe get through this. >> they add race last year and