The initial picture was found in a thread on Boston Bruins forum that I was following.
HFBoards - View Single Post - OT: Explosions at Marathon reported
Thank you, but still no link to the source of the pic. Just another board post with the same pic.
I tracked it down to here
Photo of man detained by police in #Boston #prayforboston (photo via @Eric_Twardzik) pic.twitter.com/wquciGC8KH
Thank you.