First, let me illustrate why I think Eddie Washington was acquitted.
Question: As a jurror, what's the only thing worse than letting two cold-blooded murderers walk free?
Answer: Rendering a guilty verdict based on the word of a cold-blooded murderer trying to save his own skin.
Kimani Washington (Defendant Eddie Washington's cousin) is the type of witness that defense lawyers love. We're trained to expect that the a case will be won or lost based on cross of the state's star witness. We understand that the facts that come out on cross speak louder to jurrors than even the best attorney rhetoric. It's right there, from the accuser's own mouth. Washington's changing story, history of crime, and motive to save his own skin spelled his doom under cross-examination. Against a guy like John Cunha, he didn't stand a chance.
Second, I just want to point out in fairness to the Suffolk District Attorney's office: Suffolk county juries have an unusual reputation for acquitting defendants on high-profile murder cases. Either Bostonians are inherently skeptical of authority, or we have the best criminal defense lawyers in the country. Perhaps a bit of both. For more on this interplay, take a trip back to 1770: http://www.bostonmassacre.net