How could they not know? Wasn’t an armed security guard shot through the door within nine minutes?
And that 9 minute mark jives with the audio recordings that suggest the exterior fire last about that long.
In a chaotic fluid situation such as this, let’s not rush to judgement. The tone of this seems to be that the police and SWAT had some delayed response which cost additional lives of additional victims. Let’s wait and see what comes out of the investigation.