There's no indication as of yet that he was part of a jihad, a member of a terrorist cell, or anything else besides a lunatic with a couple pistols.
They should have a public trial, public sentencing if/when found guilty and public execution if/when sentenced to death. Keep putting the info out that he's being tried for killing other people and not for his religion. If it's repeated enough, it will become fact. ;)
Of every one hundred men, ten should not even be here. Eighty are nothing but targets. Nine are real fighters, and we are lucky to have them, for they make the battle. Ah, but the One... One of them is a Warrior... He will bring the others back.
"Wrong door, buddy!"
Let no man's ghost say my training failed him.