RSBN confirmed it was a shotgun, reported at the presser. (I didn't hear it myself at the presser but I missed some of it.)
My guess (and it’s only a guess) is that the suspect bled out and then crashed.
That certainly seems plausible (assuming he did not shoot himself). There are no reports that LE engaged the gunman that I have seen so far.
Why do I hope it was a 12 ga. full choke?