Although we still have no clear motive to their horrific actions, we are learning more and more about the Tsarnaev brothers and the Boston Marathon bombings. Boston officials announced today that the brothers acted alone, but did plan on more violent attacks. Officials are hoping to gain more information from younger brother, Dzhokhar Tsarnaev, if he is ever able to speak. The reports show that the brothers threw homemade grenades and more explosives at police officers on the night that older brother, Tamerlan, was killed. Drop down for more information.