yes, but for all we know, when the first explosion went off, this guy with the white cap (especially if he had a limp arm) may have dumped the bag so he could run faster and get away from the scence, and perhaps the place he dropped his bag to be able to high-tail it out there just happened to be the same spot where the real bag for the second explosion was already placed.
Unlikely, but possible.
http://abclocal.go.com/wpvi/html5/video?id=9046095&pid=9045416§ion=null
Sunil tripathi. Went underground a month ago.
He’s one of the only people not running or hurrying in the pic at post #142.