Response: A prosecutor can gain
a tactical advantage (one, at least) from usinga grand jury to indict rather than charging by information. The O.J.
Simpson case illustrates this: In that case, the prosecutors first sought to have a
grand jury indict Mr. Simpson, since by doing this they could present
enough evidence toconvince the grand jury there was probable cause to
believe he had committed the crimes at issue, but the evidence would
be shielded by grand jury secrecy, which meant the defense attorneys would not know much about the prosecutors' case.
The defense attorneys had the sitting grand jury disqualified for
exposure to publicity (a very unusual ruling), and so the
prosecutors, out of time pressure, had to charge by information. Since they charged by information, the
defendant was entitled to a preliminary hearing, at which the defendant could
hear the testimony of the witnesses and cross-examine them. This gave
the defense a lot more information about the prosecutors' theory of the case and the
evidence they'd use to prove it.
So, if nothing else, using a grand jury indictment lets a
prosecutor avoid a
preliminary hearing and the attendant disclosure of prosecution