In American criminal law, a material witness is a person with information alleged to be material concerning a criminal proceeding. The authority to detain material witnesses dates to the First Judiciary Act of 1789, but the Bail Reform Act of 1984 most recently amended the text of the statute, and it is now codified at . The most recent version allows material witnesses to be held to ensure the giving of their testimony in criminal proceedings or to a grand jury. Since September 11, 2001, the U.S. has used the material witness statute to detain suspects without charge for indefinite periods of time, often under the rubric of securing grand-jury testimony. This use of the statute is controversial and is currently under judicial review. In Ashcroft v. al-Kidd (2011), the detainee was never charged or called as a witness, and sued John Ashcroft, then the U.S. attorney general. The Supreme Court overturned a ruling by the Ninth Circuit Court of Appeals and held that Ashcroft qualified for immunity because of his official position. Text of the statute , commonly referred to as the "material witness statute," provides as follows: If it appears from an affidavit filed by a party that the testimony of a person is material in a criminal proceeding, and if it is shown that it may become impracticable to secure the presence of the person by subpoena, a judicial officer may order the arrest of the person and treat the person in accordance with the provisions of section of this title. No material witness may be detained because of inability to comply with any condition of release if the testimony of such witness can adequately be secured by deposition, and if further detention is not necessary to prevent a failure of justice. Release of a material witness may be delayed for a reasonable period of time until the deposition of the witness can be taken pursuant to the Federal Rules of Criminal Procedure. Introduction A material witness is an individual who contains information "material" to a criminal proceeding. With the authority of , the United States government can seek a warrant from a judicial officer in order to arrest a material witness. To do so, a United States official must file an affidavit with the judicial officer alleging that (1) the individual has material information to the criminal proceeding and (2) it would be "impracticable to secure