He was charged and sentenced for destroying his computer which had information that would aid in a terrorism investigation.
His defense said the lad just wanted to go practice his religion, even though FBI agents who interviewed him in Kenya said:
"... that he would fight against any country, including the United States and his former colleagues in the U.S. Army, if Al Shabaab controlled areas were invaded or if anyone tried to institute a democratic government there."
So what happens to him when his 12 years is up? He's left to plot his way to get to heaven and those 72 virgins??
More here, and here.