Oh I don't think it was the first. When a Muslim says he is defending Islam or a call to Jihad, I think you can accept it as true.
Major Nidal Hasan would fit. The Kids that bombed Boston fit, the guy that cut off the head of woman in Oklahoma fits. Maybe more. I don't know what radicalization means? The Quran authorizes Muslims to answer the call to Jihad and defend Islam, those that do may or may not want a Caliphate, although this latest couple apparently did.
People need to read about Jihad, all sort of bad shit is authorized and believers on Jihad can act independently, no orders from the Caliph required.
Obama is lying to the American people in my opinion, at least misleading the ill informed.
http://www.answeringmuslims.com/p/jihad.html