Boston police superintendents William Evans (left) and Kevin Buckley during Mass at the Cathedral of the Holy Cross to pray for those killed or injured in the Boston bombings, in Boston yesterday. Federal investigators, questioning the bombing suspect's motives, are reviewing a visit that one of them made to Chechnya and Dagestan last year. Photograph: Josh Haner/The New York Times

As the surviving brother of the two Boston Marathon bombing suspects remained seriously ill and unable to answer questions over, further detail(...)