It’s not that they wanted to kill teens, it’s because they wanted a disruption, a distraction, and another reason to call for gun control to disarm the population.
They do NOT care who they hurt, so long as it’s not one of their own. They have no problem taking down a whole planeload of people to get a single target.
They are using panic and fear as a weapon.
But what makes you sure it’s the CIA ordering the FBI around? Can’t the NSA have a nefarious agenda, too?