Details of the Boston Marathon explosion continue to unfold. Tamerlin Tsarnaev, 26, and his younger brother, Dzhokhar Tsarnaev, 19, have been identified as lead suspects in the Boston Marathon bombing on Monday, April 15, 2013. Their mother, Zubeidat Tsarnaev, 45, was apparently placed on the CIA Terrorist Watchlist a year and a half ago.