(Watertown, MA)  --  At least seven explosive devices have been found in Boston, Cambridge and Watertown, according to NBC News.  More than 18 hours after the two suspects in the Boston Marathon bombing exchanged 200 rounds with police in a rolling gun battle, the manhunt continues in Watertown for one of the men, 19-year-old Dzhokhar Tsarnaev [[ Zoh-kar Zar-nay-ahv ]].  His 26-year-old brother, Tamerlan is dead.