The two suspects who were identified as being responsible for the shooting also robbed a 7-11 store last night near MIT in Cambridge, shot an MIT police officer to death, who was sitting in a cruiser, then car jacked a mercedes SUV. They held the driver hostage for 20 minutes and released him unharmed, but did tell the driver that they are the bombers. The police found the SUV and killed one of the bombers. The dead bomber was wearing an IUD device, they believe the other bomber is wearing one as well.
The other bomber rammed a road block with the SUV and is on the run. One neighborhood in Watertown is currently in a state of lockdown and the authorities are searching house to house and evactuating residents from every house as they go. Most of the College and Universities are closed.
They just announced that mass transit to and from the city, as well as in the city itself have shut down. They are also asking several towns to stay indoors, basically half of Boston is effected by that request.
There is also a Twitter rumor that there are 3 people are trapped in a cab which has a trunk full of explosives.