The grand jury didn't have to just sit there and listen to the Prosecutor. They were able to question the witnesses. They were able to request the production of witnesses and physical evidence; and the Prosecutor was required to produce it if it was admissible under the rules of evidence.
Maybe, just maybe, the group of people who made up the grand jury asked a lot of questions of various witnesses. Maybe they requested the testimony of real experts in law enforcement training methods and techniques. Maybe they heard from more than one pathologist. Maybe they asked for testimony from an expert in the field of cardiology. I don't know, and neither do you.
What I do know is that a reasonably large group of people were sworn as a grand jury. They reviewed all physical evidence that the Prosecutor wanted to show them, plus any other admissible evidence that they asked for. They heard from any witnesses the Prosecutor called, plus any other witnesses, requested by them, whose testimony would be relevant and admissible. After reviewing all of the evidence, that group of citizens collectively determined that there was not reasonable cause to charge anyone with a crime in this death. In other words, it would be unreasonable to charge someone.
Do you guys really want a criminal justice system, in this country, that would expose you, or a fellow citizen, to loss of life or freedom, even though a grand jury of your peers made a finding that it would be unreasonable for the government to put you on trial?
