Milton Mills Juvenile Law Lawyer, New Hampshire

A rule of evidence that disallows the use of illegally obtained evidence in criminal trials. For example, the exclusionary rule would prevent a prosecutor from introducing at trial evidence seized during an illegal search.

An affirmative defense to a crime. Self-defense is the use of reasonable force to protect oneself from an aggressor. Self-defense shields a person from criminal liability for the harm inflicted on the aggressor. For example, a robbery victim who takes the robber's weapon and uses it against the robber during a struggle won't be liable for assault and battery since he can show that his action was reasonably necessary to protect himself from imminent harm.

The amount and quality of information police must have before they can arrest or search without a warrant or that a judge must have before she will sign a search warrant allowing the police to conduct a search or arrest a suspect. Reliable information must show that it's more likely than not that a crime has occurred and the suspect is involved.

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.

Criminal Law Traffic TicketshomeGLOSSARY jury A group of people selected to apply the law, as stated by the judge, to the facts of a case and render a decision, called the verdict. Traditionally, an American jury was made up of 12 people who had to arrive at a unanimous decision. But today, in many states, juries in civil cases may be composed of as few as six members and non-unanimous verdicts may be permitted. (Most states still require 12-person, unanimous verdicts for criminal trials.) Tracing its history back over 1,000 years, the jury system was brought to England by William the Conqueror in 1066. The philosophy behind the jury system is that--especially in a criminal case--an accused's guilt or innocence should be judged by a group of people from her community ('a jury of her peers'). Recently, some courts have been experimenting with increasing the traditionally rather passive role of the jury by encouraging jurors to take notes and ask questions.

A term lawyers use to describe the courts and other bureaucracies that handle American's criminal legal business, including offices of various state and federal prosecutors and public defenders. Many people caught up in this system refer to it by less flattering names.

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).