on emergency deployment. we are working 12-hour shifts and there will be a significant police presence throughout the city. please give us some space around the copley area as we process this scene. again, if there are any -- any pieces of information or photos from the incident, getting those to the two tip lines, the fbi tip line primarily, they are now in charge of the investigation because of the nature of this investigation, as well as the boston police line at 1-800-494-tips. i would like to invite the district attorney to say a few words. >> thank you very much, commissioner. earlier this afternoon, like so many bostonians, i was on boylston street near the finish line. had left about 30 minutes before this incident occurred. a short time ago, commissioner davis, myself, colonel alben and special agent delorea and our top staff went down to the scene. it was a large and disturbing