De Young White Collar Crime Lawyer, Pennsylvania

A crime, less serious than a felony, punishable by no more than one year in jail. Petty theft (of articles worth less than a certain amount), first-time drunk driving and leaving the scene of an accident are all common misdemeanors.

The crime of operating a motor vehicle while under the influence of alcohol or drugs, including prescription drugs. Complete intoxication is not required; the level of alcohol or drugs in the driver's body must simply be enough to prevent him from thinking clearly or driving safely. State laws specify the levels of blood alcohol content at which a person is presumed to be under the influence. Also called driving while intoxicated (DWI and drunk driving).

A formal accusation of criminal activity. The prosecuting attorney decides on the charges, after reviewing police reports, witness statements and any other evidence of wrongdoing. Formal charges are announced at an arrested person's arraignment.

Latin for a 'guilty act.' The actus reus is the act which, in combination with a certain mental state, such as intent or recklessness, constitutes a crime. For example, the crime of theft requires physically taking something (the actus reus) coupled with the intent to permanently deprive the owner of the object (the mental state, or mens rea).

Someone who intentionally helps another person commit a felony by giving advice before the crime or helping to conceal the evidence or the perpetrator. An accessory is usually not physically present during the crime. For example, hiding a robber who is being sought by the police might make you an 'accessory after the fact' to a robbery. Compare accomplice.

One of the most sacred principles in the American criminal justice system, holding that a defendant is innocent until proven guilty. In other words, the prosecution must prove, beyond a reasonable doubt, each element of the crime charged.

A formal investigation -- governed by court rules -- that is conducted before trial. Discovery allows one party to question other parties, and sometimes witnesses. It also allows one party to force the others to produce requested documents or other physical evidence. The most common types of discovery are interrogatories, consisting of written questions the other party must answer under penalty of perjury, and depositions, which involve an in-person session at which one party to a lawsuit has the opportunity to ask oral questions of the other party or her witnesses under oath while a written transcript is made by a court reporter. Other types of pretrial discovery consist of written requests to produce documents and requests for admissions, by which one party asks the other to admit or deny key facts in the case. One major purpose of discovery is to assess the strength or weakness of an opponent's case, with the idea of opening settlement talks. Another is to gather information to use at trial. Discovery is also present in criminal cases, in which by law the prosecutor must turn over to the defense any witness statements and any evidence that might tend to exonerate the defendant. Depending on the rules of the court, the defendant may also be obliged to share evidence with the prosecutor.