They are the Massachusetts National Guard's 1st Civil Support Team: http://www.dailypaul.com/282579/identity-of-the-men-in-black...
Also, suspect #2 is NOT wearing a backpack in the post-blast photo:
Check out the Laissez-Faire Journal at LFJournal.com
"The State is a gang of thieves writ large." - Murray Rothbard
Want DP delivered to your inbox daily? Subscribe here:<