Apparently they identified, tracked down, and cornered the bomber, who blew himself up (or was shot, or both).
@RockChalkinTexas I hope you have been okay through all this. Unfortunately, I know what a widespread community fear of random violence is like, because we lived in the VA suburbs of DC during the Oct 2002 sniper shootings very close to a couple incidents. My heart goes out to all you Austinians and hope they soon announce all his devices have been located so you all can enjoy a sense of relief and a return to normalcy.