Legal Question in Criminal Law in California

Re: pleminary hearing

The prosecutor's client is the government, which really doesn't need protection. You probably meant to ask about defense counsel.

At a prelim, the task of the defendant's attorney is to show how weak the prosecution's evidence is. If it seems weak enough and/or has significant gaps, some or all of the charges may be dismissed. It is rare for the entire case to be dismissed at a prelim, though, since the government need only prove that it has enough evidence to persuade a reasonable jury to convict the defendant. It does not have to prove its case beyond a reasonable doubt at the prelim; such proof is only necessary at trial.

Note also that defense counsel usually won't present much evidence on his client's behalf at the prelim. The prelim is a test of the prosecutor's evidence, not the defendant's. Revealing the defendant's evidence and strategy at a prelim would usually do nothing for the defendant but would help the prosecutor prepare better for trial.