SAN`A, Yemen - A suspected al-Qaida ally was executed by a Yemeni firing squad Sunday after being convicted of killing a prominent politician and plotting a deadly attack on three American missionaries in 2002. Ali al-Jarallah was blindfolded and shot in the courtyard of the central prison in the capital, San`a, in the presence of judiciary officials, several reporters and the victim's lawyer. Al-Jarallah was convicted in 2003 of helping plot the attack that killed three missionaries in a Yemeni hospital. He also was convicted of murdering Jarallah Omar, the Yemeni Socialist Party's deputy secretary-general, a few days earlier, and...