diffused. on the other hand you have to figure if you re a policeman in watertown or cambridge, going door-to-door, you have a policeman who has been killed, three people at the marathon have been killed. another policeman who has been grievously wounded, a fellow who indicated he has gun and also that he has explosives. i can t imagine you re going to take too many chances if you come face-to-face with dzhokar tsarnev but they want to figure out what was involved here, why these two fell lows apparently were involved the two brothers in the marathon bombing. was this domestic terrorism? was there some international connection as you report all day? the older brother, tamerlan, had gone to russia for several months. did he make connections there with al qaeda or islamic radicals? or chechenables or whatever.