What did police know as the Uvalde school shooting unfolded?

As investigators dig deeper into the law enforcement response to the deadly school shooting, in Uvalde, Texas, a host of disturbing questions remain about what officers on the scene knew as the attack was unfolding. Did they know children were trapped in a classroom with the gunman? Was that potentially critical information relayed to the incident commander on the scene? And did officers challenge the commander’s decision not to promptly storm the classroom?