the wrong time. you mentioned the shooting in cambridge at the campus of m.i.t. and campus police officer was responding to reports of a disturbance when he was shot. he was taken to the hospital where he was pronounced dead and officials began an investigation in this case that was the first incidence of violence this evening and led to a number of situations across the area. i want to go to lester holt who is live in watertown, massachusetts, which is about 4 1/2 miles from cambridge where all of this started. what can you tell us about what's happening on the ground right now? >> well, they have moved the press and citizens back. they've cordoned off what appears to be a few square miles of this area while they work that scene that we've been watching in those skype photos. the s.w.a.t. teams, we were in another location about five minutes from here, a bit closer earlier. there were s.w.a.t. teams that were working slowly up and down the street that i could see in