If you are arrested in Pennsylvania and charged with a serious crime, such as a misdemeanor or felony, a preliminary hearing before a magistrate will be scheduled promptly. In the first instance, the purpose of a preliminary hearing is to protect the right of the accused against unlawful arrest and detention.
It is important to recognize that a preliminary hearing is not a formal trial on the merits of the case. The object of a preliminary hearing is to see whether the government can show that there is sufficient evidence to establish that a crime was committed and a reasonable probability that the defendant can be connected to the crime charged. Stated differently, a preliminary hearing is held to determine whether the accused should be bound over for trial or released; if the accused is bound over, a determination is then made whether the accused will be released on bail (and the amount of bail) pending a criminal trial.
At the time of the preliminary hearing, the judge, usually a magisterial district judge, must decide whether there is a “prima facie case” that a crime has been committed and that the accused has committed it. The burden of establishing a prima facie case is on the Commonwealth, and it is a low one. It is important to note that the Commonwealth does not need to prove that a crime occurred beyond a reasonable doubt; it must only establish that there is some evidence supporting each element of the crime charged. Importantly, the judge at a preliminary hearing is allowed to consider the evidence presented in the light most favorable to the Commonwealth. Accordingly, in the vast majority of cases the accused at a preliminary hearing is usually bound over for trial in the county Court of Common Pleas. As long as the government can show that a crime was committed and there is some likelihood, however small, that the accused committed the crime, he or she will typically be required to appear for a criminal trial.
One of the major differences between the conduct of a preliminary hearing and the conduct of a criminal trial relates to the rules of evidence and the constitutional protections which apply. Hearsay evidence is generally permitted at preliminary hearings. Thus, written and oral statements by witnesses who are not present in court to be cross-examined may generally be used in a preliminary hearing where such statements would never be allowed at a criminal trial. Similarly, the constitutional right of the accused to confront witnesses against him generally does not apply in a preliminary hearing whereas this constitutional right will always apply in a criminal trial. It is thus easy to see why the accused has a difficult time “winning” at a preliminary hearing.
In some cases the accused may be successful at challenging the charges at a preliminary hearing. One example would be an irrefutable alibi – such as a showing that the accused was physically outside the jurisdiction when the crime was committed. (It’s hard to steal a car in Pennsylvania when you can prove you were in California. . .) These cases are the exception – criminal charges would rarely be brought in such circumstances.
— Kevin Palmer