Did the Boston terrorists get help building bombs?

http://www.cnn.com/2015/04/09/politics/boston-terrorists-tsarnaev-brothers-help-building-bombs/index.html

After the Boston bombing last year, many people still wonder if the terrorists had help performing the act. In a motion filled last May, federal prosecutors asserted that interviews with Dzhokhar Tsarnaev, terrorist, "provided reason to believe that the Tsarnaevs had accomplices". Now, a year after the tragic shooting, Boston police commissioner Ed Davis told CNN he suspected the brothers had help to carry out their plan. CNN's justice reporter Evan Perez said, " Someone who might have either assisted in making the bomb, perhaps helped test it, perhaps the components-- that's part of the investigation thats still ongoing, because they've never closed those questions".

This is related to our AP Gov class because it involves our Federal government system. Specifically the Judicial branch because federal prosecutors were involved. The brothers had several interviews with the FBI as well.

I think that even though his trial has ended and he was found guilty, the court needs to reevaluate his trial and see if they can find some more suspects that could have assisted him. This may be a waste of time since all the drama about the bombing has died down. Im sure people who were affected personally, would appreciate more of an explanation as to what happened, how and why.