Following the Boston Marathon terrorist attacks that killed three people and injured over 170, President Obama addressed the nation: "We still do not know who did this or why.... [M]ake no mistake -- we will get to the bottom of this. And we will find out who did this; we'll find out why they did this." It should be noted that it is premature to say if the Boston Marathon attacks are acts of "terrorism" under the definition found in U.S. law: "premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents."
By Friday night the "who" question was (as best we know) answered with the death and arrest of the two suspected perpetrators, Tamerlan and Dzhokhar Tsarnaev. In the following days, headlines began to focus on the "why": Washington Post: "Search for Why Begins in Boston Marathon Bombings"; Chicago Tribune: "Boston Marathon Bombing Investigation Turns to Motive"; and Financial Times: "FBI Searches for Bombing Motive." Working off whatever unverified information they came across, experts, policymakers, and others felt comfortable guessing what motivated the two suspects, with their uncle providing the most concise explanation: "Being losers."