The first blast comes at 2.50pm as runners finish the marathon, on the pavement behind crowds to the left of the athletes’ route just a few hundred feet before of the finish line.
Just 13 seconds after the first blast, a second explosion occurs less than 100m away, on the same side of the road, further back along the route.
A third explosive device is found after the finish line, and is destroyed by authorities.
John F Kennedy Public Library
An incident, possibly a fire, is reported at the nearby John F Kennedy Library. It is still unclear whether this is related to the bombings, or whether it was an unrelated fire. An investigation is ongoing.