"They not only investigated the older brother; they interviewed the older brother. They concluded that there were no signs that he was engaging in extremist activity. Based on what I've seen so far, the FBI performed its duties. Department of Homeland Security did what it was supposed to be doing. But this is hard stuff."
President Barack Obama defending the FBI's 2011 investigation of the late Tamerlan Tsarnaev, one of the suspects in the April 15 Boston Marathon bombing.