Literally just confirmed by TX DPS Spokesman Victor Escalon:

11:28 suspect wrecked in ditch with NO prior engagement.
11:30 911 call
11:40 suspect enters school, after firing shots between the ditch and school building
11:44 local officers make entry into school and are repelled by shooter, who then barricades himself in classroom
12:44 (approximately) BORTAC kills suspect
NO armed officer available at time suspect entered school

So, complete and abject failure in initial response followed by severely delayed final entry. No telling how many kids died in the interim.

And again, no duty to protect, so government will find themselves not criminally responsible

Authority without responsibility, is tyranny.