Early info is almost always wrong. For the uninvolved, a 72-hour waiting period for news to sort itself out is not a bad idea.
"Fog of war" is only part of the reason for this. Ineptitude and a CYA impulse on the part of the authorities work into it too.
The similarities among these (Columbine, Sandy Hook, Parkland, Uvalde, others) indicate that the experts in charge of designing and enacting defenses and responses are wrong.
Adults in charge of children must answer this question: What do you do if a killer walks into the room today? (Answers invoking the need to change laws or improve mental health services earn a failing score.)
A teacher who uses her body as a shield in a doomed effort to protect her students is a martyr. A teacher who pulls out a gun and shoots the killer before he can murder the children is a hero.
The time to stop a killer is before he gets into that room.
Responding to an "active shooter" is not just the police department's job. The true first responders are and must be the adults who work at the school.
An ounce of door-lock prevention is worth a pound of trigger-pulling cure. Or more.
Attitude trumps training. Bureaucracies including police departments and school systems often use training programs more as political theater than as rigorous preparation. The result may be individuals with safety certifications but no steel in their spines. You know who doesn't have any training? These young killers. They are not trained assassins. They never attended some terrorist training camp in Iraq. What's needed are adults who have the personality to play the sheepdog to the killer's wolf. The kind who run to trouble, not away from it. People who will pull the trigger when the trigger needs to be pulled. Hunters. Boxers. Guys who like to mix it up once in a while.
We also need people who can lock a damned door, and supervisors who require it.