I found the bit of information I was waiting for.  The security guard at the school in Minnesota was unarmed.  It took men with guns (the police) to stop him.  The teachers (and probably the security guard) were disarmed by law and were unable to provide effective protection.  How long will it be before the lawmakers in this country figure out what others already know about how to prevent or at least drastically reduce the damage of, these type of events?