`` I 'm pretty sure someone from outside did it , '' Delima said . NEW : School 's president : ` ` These are just people who did very , very stupid things '' NEW : School police chief : Report that a student is behind the attack . Police interview a ` ` person of interest , '' search for another . Federal authorities ATF , U.S. marshals offer assistance .
NEW : School 's president : ` ` These are just people who did very , very stupid things '' NEW : School police chief : Report that a student is behind the attack . Police interview a ` ` person of interest , '' search for another . Federal authorities ATF , U.S. marshals offer assistance .