Al Qaeda Leader: ‘Gravest Consequences’ if Boston Bomber Executed

Al Qaeda leader Ayman al-Zawahri said in an online video message that convicted Boston Marathon bomber Dzhokhar Tsarnaev should not be executed, and that there would be the “gravest consequences” if the U.S. carries out his death sentence. Tsarnaev was sentenced last year to death by lethal injection. The 2013 attack on the Boston Marathon killed three people and injured hundreds of others.