That isn’t Dzhokhar, that is the track coach (Yassine Zaimi) of the kid in blue who came forward when he saw his photos on the internet (like this one). Those two were cleared by the FBI.
http://www.thesmokinggun.com/buster/runners-fingered-as-bombing-suspects-875362
What I'm saying is that you have teams of two; 1 is bomb carrier, the other is the spotter. That it's possible Tamerlan wasn't actually carrying a bomb (his younger brother was), and that the "cleared" coach was carrying the other along with his spotter.
Probably one or two other teams involved as well but they didn't execute for one reason or another.