scene in boston. you're speaking with law enforcement, local, state, federal law enforcement types. any sense of sort of a general description of where this investigation stands right now, infancy, middle, advanced, anything along those lines? >> earlier in the week we were told forensic teams were expected to wrap up toward the end of the week. there's been no update on that. we're not clear whether in fact they have gotten all the evidence they need from various locations. the one by the tree where one device went off and also by the finish line where another device went off. they've been canvasing the area now and we're told that there were other people. through the last couple days we've seen a number of photographs of people who investigators are interested in speaking with. it'll be very, very interesting if the photographs that we have seen are an individual or