Milton Keynes Juvenile Law Lawyer, England

Latin for 'You have the body.' A prisoner files a petition for writ of habeas corpus in order to challenge the authority of the prison or jail warden to continue to hold him. If the judge orders a hearing after reading the writ, the prisoner gets to argue that his confinement is illegal. These writs are frequently filed by convicted prisoners who challenge their conviction on the grounds that the trial attorney failed to prepare the defense and was incompetent. Prisoners sentenced to death also file habeas petitions challenging the constitutionality of the state death penalty law. Habeas writs are different from and do not replace appeals, which are arguments for reversal of a conviction based on claims that the judge conducted the trial improperly. Often, convicted prisoners file both.

In criminal cases, a group that decides whether there is enough evidence to justify an indictment (formal charges) and a trial. A grand jury indictment is the first step, after arrest, in any formal prosecution of a felony.

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 peace officer for a particular geographic area -- most often a rural county -- who commonly has the power to serve legal papers, arrest lawbreakers and keep the peace. Depending on the state, a constable may be similar to a marshal or sheriff.

A mental defect or disease that makes it impossible for a person to understand the wrongfulness of his acts or, even if he understands them, to ditinguish right from wrong. Defendants who are criminally insane cannot be convicted of a crime, since criminal conduct involves the conscious intent to do wrong -- a choice that the criminally insane cannot meaningfully make. See also irresistible impulse; McNaghten Rule.

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 serious crime (contrasted with misdemeanors and infractions, less serious crimes), usually punishable by a prison term of more than one year or, in some cases, by death. For example, murder, extortion and kidnapping are felonies; a minor fist fight is usually charged as a misdemeanor, and a speeding ticket is generally an infraction.

A decision by a judge or jury that a defendant in a criminal case is not guilty of a crime. An acquittal is not a finding of innocence; it is simply a conclusion that the prosecution has not proved its case beyond a reasonable doubt.

Laws written by Congress and state legislators that make certain behavior illegal and punishable by fines and/or imprisonment. By contrast, civil laws are not punishable by imprisonment. In order to be found guilty of a criminal law, the prosecution must show that the defendant intended to act as he did; in civil law, you may sometimes be responsible for your actions even though you did not intend the consequences. For example, civil law makes you financially responsible for a car accident you caused but didn't intend.