I was on a Federal Grand Jury back in 2002. Our job was not hard. We did not have to deliberate more than 20 minutes over any case, and we almost always voted to indict. Why? Because we were simply an insurance against vindictive Federal prosecution. We were there to listen to a prosecutor's (and only a prosecutor's) basic case and vote as to whether there was enough evidence to warrant using public resources for a trial. We did not have to find "beyond a reasonable doubt," we simply had to find that there was sufficient evidence to proceed. Easy peasy. That's what grand juries do. I can only recall one case out of well over 100 that we heard where we voted not to indict, and it was because the prosecutor did basically the legal version of a horrible last-minute book report.
Of course, the thirty or so of us were a well-integrated bunch. Every demographic you could think of was represented. Everyone was heard. Nobody was bullied. We were the Los Angeles melting pot at its best.
How the hell do you fail to indict given even a portion of what has been picked over in public... unless the jury doesn't represent the best that Jefferson County has to offer?