It's almost 3 a.m. here, 6 am there, and the start of the day.  But Watertown is locked down--no transit, no businesses opening, nobody going out or in.  Pete Williams is reporting that the police believe they know the building where the guy at large is holed up.  That answers my question, which is how do they know that he is still in Watertown.  He got away reportedly by flooring an SUV and breaking through police lines.  It would seem he would drive as far as he could.  But they believe they know where he is.

These guys were heavily armed with guns and explosives.  Nobody knows what the guy on the run has with him.

I've been away from the TV for a half hour or so, not much has changed, and the print media via goggle news seems to have caught up.