may be, but it does not seem the only singular source stating the same version of events. nothing is for certain, of course, but so far it seems to be of what had happened.
so far is seems the SRO and police did nothing at all, with a strategic tactical wait approach, with border folks coming in to the scene as their kids were in that school. in desperation they called in their homies/husbands on patrol, and that group came and stormed into the building ignoring cops. if you have a better version - tell me, but it sounds realistic enough to me.
Customs and Border Protection is a ubiquitous presence in many Texas communities, and agents are often first responders.
www.texasmonthly.com
PS. that also explains why perp is dead and not presented now as a prized trophy on all the TV screens.
PPS.
'More could have been done': Witnesses question law enforcement response to Texas school shooting