Related Content: Boston bombings
The latest on the Boston bombing investigation including the arrest of Dzokhar Tsarnaev’s three friends. Also, President Obama renews his commitment to close Guantanamo Bay. Plus, Obama's second-term agenda is being tested by unexpected events. Joining Gwen: Pete Williams, NBC News; Michael Duffy, TIME; Doyle McManus, Los Angeles Times; and Christi Parson of Tribune.