Preliminary hearings are held only in cases in which a defendant pleads not guilty at the arraignment or initial appearance. But even then, whether a preliminary hearing will be held depends upon the laws of each state. In some states, preliminary hearings are held in every criminal case. In other states, they are held only if the defense requests them. In still other states, they are held only in felony cases.
In many states, the prosecutor may eliminate the need for a preliminary hearing altogether by convening a grand jury and obtaining an indictment. And, for strategic reasons, defendants may decide to waive (give up) their right to the preliminary hearing altogether and proceed directly to trial.
The preliminary hearing typically takes place soon after charges are officially filed against the defendant. For instance, under the Federal Speedy Trial Act, a preliminary hearing must normally be held within 30 days of the time the defendant is arrested. (See 18 U.S.C. § 3161.) Many states have similar time frames.
As it happens, defendants can and often do "waive time"—that is, give up their right to a speedy trial—which allows the preliminary hearing to be delayed to a time convenient for all the major players in the case. Delays usually benefit the defense, which is why it's very common for defendants—on the advice of their attorneys—to agree to waive time.
In some ways, preliminary hearings are previews of what the trial will be like, if the case gets that far (most don't). A prosecutor offers testimony from witnesses and may also introduce case-related evidence, such as a weapon.
Typically, prosecutors present only enough evidence to convince the judge that there is probable cause to hold the defendant for trial.The defense has the right to—and most often will—cross-examine prosecution witnesses both to find out more about their observations and to test their demeanor. This helps the defense prepare to cross-examine these witnesses at trial and may also present defense attorneys with information that they can use to improve their positions in plea negotiations. After the prosecution is finished with its presentation, the defense has the right to put on its own case, but is not required to do so—and usually doesn't.
Many of the same procedural rules that govern trials apply in preliminary hearings. For example, ordinary witnesses (nonexperts) may testify only to what they have perceived; they may not give opinions. And the defense and prosecution may object to evidence and testimony offered by the other side.
However, one important difference between preliminary hearings and trials is that frequently hearsay evidence is admissible in prelims.
Preliminary hearings usually are conducted in open court where the public, the defendant and defendant's family, any victims, the media, and any other interested people may all be present. In rare cases, however, the judge may decide to close the courtroom (for example, in the case of a sex crime where the victim is a child).
A preliminary hearing usually has one of three outcomes:
After a defendant is bound over for trial, a prosecutor typically files a separate document (often called an "information"), which signals the start of further court proceedings.
Defendants who are free on bail normally remain free following the prelim, but are required to appear in court at the next scheduled hearing. In-custody defendants stay in jail awaiting their next court appearance, although they can renew their request for bail at the prelim. Bail is always reviewable, and a judge might grant bail if the actual facts (as presented at the prelim) are not as bad as the police report made them sound.
At this point, depending on the jurisdiction and the seriousness of the crime, the case will proceed in one of these ways: