Well, from my understanding of our system, the prosecutors are supposed to be pushing for a conviction if there’s an indictment handed down. The grand jury will be the first step — of “citizens” deciding whether something should be prosecuted or not. And if it should be (according to a grand jury, of citizens) then the prosecutor is supposed to be doing all he can to convict.
That’s once it’s decided, by an indictment, that one should proceed to convict in the first place. The “other side” (the defense) is then supposed to be doing all it can to defend the accused.
Each side is supposed to be doing their part, the prosecution to convict and the defense to acquit.
But, the process doesn’t even start unless a grand jury — of citizens — hands down the indictment in the first place. And then one doesn’t get convicted unless a jury — of citizens — convicts.
Thus, the greater responsibility — from the way I see it — is with the citizens of the grand jury and the citizens of the jury.
That’s where the main responsibility lies...
You are incorrect. Whether it is a grand jury or a district magistrate that determines whether there is evidence to proceed with the trial it is the prosecutor that presents such evidence, and the goal, anyway, of the prosecutor is (supposedly) not to get a conviction but to see justice done.
IOW, if the prosecutor should come across information -- and the prosecutor should be open to such information -- the prosecutor has an obligation to stop the trial.
Apparently, in this case neither the prosecutor nor the investigators even bothered considering DNA evidence.