Zubeidat Tsarnaeva, the mother of Tamerlan and Dzhokhar Tsarnaev, the two suspects in the Boston Marathon bomb attack of 15 April, says she is sure her children were not involved. Tamerlan Tsarnaeva, 26, died following a shootout with Boston police and Dzhokhar, 19, is in hospital after being discovered hiding in a boat in Watertown, Massachusetts
