One thing that could help push it deeper onto the media's radar...
IOTL, the perpetrators shouted the N Word when killing black students, though this doesn't seem to have been motivated by any deeply-held racial ideology, but was probably just more in imitation of usage of that same word in violent pop-culture scenarios(eg. Tarantino's films).
If they decide to carry out their attack in the weeks after 9/11, and nihilistically shout stuff like "Al Qaeda Rules!!" while mowing down their victims, you can bet that the media is going to fixate on that for at least a moderate duration of time, even though it'll eventually turn out to be a blind alley. And there will be a few cranks on the Islamophobic far-right who will continue to insist, against all evidence, that Harris and Klebold were somehow in alliance with Al Qaeda, but THE LIBERAL MEDIA IS COVERING IT UP!!