I wasn't discussing theoretical cases - I posted about 2 recent cases (one involving a police officer and another involving a private citizen) wherein someone was arrested prior to an indictment. Actual cases - not theoretical cases.
Personally, I have no problem with waiting for the decision of the St. Louis County Grand Jury. You won't see or hear me calling for Officer Wilson's head on a pike unless evidence shows that he acted unlawfully.
I was merely reporting the facts of due process, to wit: an indictment isn't necessary in order to arrest someone. Probable cause is all that's necessary in order to make an arrest.
Folks can decide for themselves whether or not they believe probable cause exists or whether or not they agree with the Brown family attorney. I haven't made any statement whatsoever about Mr. Gray's assertions.
I think a lot also depends on police procedure followed in that jurisdiction. In my city, all officer involved shootings are investigated by a Grand Jury. No probable cause currently exists because Officer Wilson was allowed, by law, to discharge his weapon in the line of duty. The "justified shooting" has to be first determined for an arrest. So it is a different standard.