Source for first part of article: http://www.wtsp.com/news/article/311478/81/Snopescom-scopes-out-Boston-Marathon-conspiracies
The WTSP site has summarized what Snopes.com has written about the Boston Marathon bombings and related conspiracy theories. There are 5 main categories that Snopes outlines in relation to these tragedies. One is early creation Facebook pages. In other words, before a tragedy happens, someone expresses condolences about what happened, which seems impossible. Snopes' opinion is said to be that Facebook dates are not reliable. My own thought on this is that why would someone who is part of a conspiracy make such a post in the first place, knowing it would give things away?
A Sandy Hook child was supposedly killed in the bombing. Scopes, according to this article, states that this is not possible; for one reason, children aren't allowed to run in the marathon. However, I have heard that the child was waiting on the finish line.
Another conspiracy theory centres around the false victim scenario. According to http://www.snopes.com/politics/conspiracy/boston.asp#vogt), (Source for both pictures), sometimes one of the aspects of conspiracy theories that creates a lot of controversy is dual pictures of the same person. Why would the same person be involved in both tragedies, the reasoning goes, unless they are paid actors, like Robbie Parker allegedly was regarding Sandy Hook? However, Snopes states that Nick Vogt and Jeff Bauman are two separate people, in reference to the first displayed picture. Another example includes the Sandy Hook Principal, Dawn Hochsprung, relevant to the second picture. According to Snopes, there is also a woman named Donna Bruce who was interviewed in relation to the Boston Marathon bombings. So according to Snopes, the same woman was not involved in both tragedies. It is easy to manipulate pictures to say whatever name you want, after all. For another comparison, check out this article that I wrote a while back:
What do you think?