Mr. Muhammad, 24, a Muslim convert from Memphis, spent about 16 months in Yemen starting in the fall of 2007, ostensibly teaching English and learning Arabic. During that time, he married a woman from south Yemen. But he was also imprisoned for several months because he overstayed his visa and was holding a fraudulent Somali passport, the Yemen government said.
Under pressure from the United States government, Yemen deported Mr. Muhammad in late January 2009. But just four months after his return, Mr. Muhammad used a semiautomatic rifle to gun down two soldiers — Pvt. William A. Long and Pvt. Quinton Ezeagwula — while they were standing outside a military recruiting station in Little Rock, killing Private Long and wounding Private Ezeagwula.

