Dennis Lehane is the author of several fine urban historical novels. He is a native of Boston and still lives in Dorchester, the home of the eight-year-old killed in the Boston Marathon bombing. I strongly recommend his op-ed piece in the New York Times which you can find here.
I often tell students when I teach the American Revolution that the Boston Massacre was no massacre at all--five people killed. The name "massacre" was bestowed upon it by patriot propagandists in very short order, along with Paul Revere's incendiary and wildly inaccurate engraving of the massacre--something widely known to everyone who's gotten past second grade in this country.
Today, of course, we don't need the imaginations of illustrators and engravers. The cellphone cameras and videos captured the horrific details: more video footage to add to our grisly collective library of terrorist damage.
Do read Dennis Lehane's posting: it says much about Boston and its character.