Fox News, who at first suggested it was merely a construction or gas line explosion.

Now they are saying that the authorities have determined it was a terrorist attack, because there were devices set that contained ball bearings. The two explosions were about 15-20 seconds apart and on opposite sides of the street. Two other unexploded devices have been located and since the original explosion the JFK library in Dorchester, Mass (a short distance away) has also had an explosion.