BPD now say the explosion at the JFK library is linked to those at the Marathon, and to the other bombs found. That is a reversal from what was said earlier. (ETA: that has again been reversed, police now saying that there is no connection.) The JFK library is in a part of Boston that is not particularly close to the end of the Marathon route. BPD have asked people in Boston not to congregate in large groups. They have asked people not to come into the city. To stay at home, or to go home if at all possible. The police are currently inspecting all the discarded packages left behind by the runners. Which, let me tell you, is a lot of packages.