Pretty much everyone is aware of the threats made earlier during the concert. Also, he was gaming on her high rollers card, which was found in the room, I believe.
If Ma Barker gets pinched 12 hour’s flight time away from the scene, 6 hours after the event, she wasn’t making threats, or in the room, or actively participating, and therefore perhaps an uncontained threat.
Teading more than that, into LE statements seems risky.
I don’t think she was involved in actually shooting people and I do not think anyone else was actually shooting other than Paddock.
However, it would be odd if there wasn’t at least some hint this man was “off” or at least involved activities or beliefs that could point to a motive.