Teachers were no longer reporting incidents because they were afraid of being branded as racist since many of these incidents involved minority students.
Because of the new reporting (or non-reporting) system, the murderer had 21 incidents at the school that were not referred to the police. The police then were called to his home 39 times. Not once was this person taken to the police station and charged with anything and kept overnight. If just once he had been, he would not have passed his background check and he would never have been able to acquire a legal weapon of any kind.