wait a second...
virtually EVERY story has the bomb strapped to him....
now it was a backpack?
WTF?
He was removing the bombing materials from a backpack to put them in a vest and most assume to go back in as they don't pat people down, take off the vest and detonate it that way. Instead something happened and it blew up while he was sitting on the bench. The bomb had a directional device and they have found metal in the trees. There was a second backpack which Boren first said was blown up and then said it had nothing in it but that was not the facts according to sources in Norman PD. The 2nd backpack also contained a bomb.