Nice of the local police force to wait on him to drive all that way to get the honor of going in first. (/sarc, of course)
The biggest & longest part of the crime is that this creep shooter told the world for the past 4 years WHAT he intended to do.
Has anybody brought up the suspicion that the Border Patrol agent may have had some inside information that some part of the Mexican cartels were involved, in arming the perp with obviously relatively high-value rifles and a generous supply of ammunition? The grandfather had been involved at some time in the past with drug possession, and maybe knows a lot more of the connections than he is letting on.
The cartels have much of the local police and border agents under surveillance, and may have passed a not so subtle message to “Stay out, or we come after ALL your families!” to a number of these same law enforcement officers.
The perp was clearly from a very dysfunctional family and the very kind of target the cartel would choose to carry out some of their undercover operations, like drivers of vehicles standing by to whisk smuggled drugs and human traffic to distant location beyond the easy reach of the border agents. Not that much of a stretch to extend that to other terrorist acts, like taking the hostages and going on a killing spree at the school.
Just scattering some dots, which may or may not be connected. Occam’s Razor, in which a simpler explanation may very well be closer to the truth.