Speculation on events like the recent Boston Bombing are fraught with difficulties, but one should examine all the possibilities. People might want to look into recent problems Boston's mob is having in the courts (http://www.boston.com/...). The bombing could be a threat of what is to come. It has been noted that the bombing took place in the last mile dedicated to the children murdered by the madman at Sandy Hook (lets stop calling them "gunmen). This could be interpreted as a specific threat to the children of prosecutors, judges and politicians in Boston.
The Associated Press reported on March 4th 2013 that the judge in the Boston Mobster James "Whitey" Bulger case that he cannot introduce evidence that he was offered immunity from his crimes. The case is due to go to trial on June 6th and he is accused of involvement in 19 murders. Boston is a city divided by crime families and ethnic tensions, support for Bulger has become strident and he is often described by his supporters as a hero. A recent book on Bulger by Cullen and Murphy (http://books.wwnorton.com/...)details his history in Boston and the support he was built.
More important to the Boston bombing is the trail of violence and terror that gangs in America has wrought recently including assassinations of prosecutors, judges and police. The recent murder in Colorado of the Prison chief is a prime example (http://www.nydailynews.com/...). Prison gangs in Texas have been tied to a growing national linkup (http://www.reuters.com/...). This ties in with efforts to control weapons like military assault weapons and large clips, cop killer bullets and registration of sales. A growing gang organization, well armed and organized endangers the ability of society to protect itself and to provide a safe and free environment.