Not exactly. They already know the answer, or think they do.
And they aren't interested in justice, they want revenge and/or a win.
BTW, IMO any homicide, by anybody for any reason, should be reviewed by a jury similar to the old-time coroner's inquest, to determine if the homicide was justified or not. If not, then it goes to the grand jury to determine if there's sufficient evidence to take it to trial. This would apply to cops as well as civilians. No "departmental review" so they can piss milk on each other.
To my mind, the present system of leaving justified or not up to the secret determination of a GJ or, worse, administrative decision by an elected or appointed prosecutor, does no service to any of the parties involved.
Note what happened to Zimmerman. A prosecutor determined the homicide was justified, then that was overruled by political pressure. If a jury of the type I describe had ruled the killing was justified, in open court, it would have at least greatly reduced the perception of secret double-dealing that was behind much of the furore.
What you say makes sense, but look at this case.
Nothing that has been revealed has swayed the Brown defenders one iota.
They’re angry, and nothing is going to pacify them but rioting in the streets.
Toss in some Leftist anarchists, and you’ve got just the right ingredients for a disaster.