Nathalie Felony Lawyer, Virginia

An exception to the general rule that a police officer needs an arrest warrant before he can enter a home to make an arrest. If a felony has just occurred and an officer has chased a suspect to a private house, the officer can forcefully enter the house in order to prevent the suspect from escaping or hiding or destroying evidence.

A document issued by a judge or magistrate that authorizes the police to arrest someone. Warrants are issued when law enforcement personnel present evidence to the judge or magistrate that convinces her that it is reasonably likely that a crime has taken place and that the person to be named in the warrant is criminally responsible for that crime.

The mental component of criminal liability. To be guilty of most crimes, a defendant must have committed the criminal act (the actus reus) in a certain mental state (the mens rea). The mens rea of robbery, for example, is the intent to permanently deprive the owner of his property.

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.

The killing of one human being by the act or omission of another. The term applies to all such killings, whether criminal or not. Homicide is considered noncriminal in a number of situations, including deaths as the result of war and putting someone to death by the valid sentence of a court. Killing may also be legally justified or excused, as it is in cases of self-defense or when someone is killed by another person who is attempting to prevent a violent felony. Criminal homicide occurs when a person purposely, knowingly, recklessly or negligently causes the death of another. Murder and manslaughter are both examples of criminal homicide.

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.

A situation in which the police detain a person in a manner that, to any reasonable person, makes it clear she is not free to leave. A person can be 'under arrest' even though the police have not announced it; nor are handcuffs or physical restraint necessary. Questioning an arrested person about her involvement in or knowledge of a crime must be preceded by the Miranda warnings if the police intend to use the answers against the person in a criminal case. If the arrested person chooses to remain silent, the questioning must stop.