Detainer (from detain, Latin detinere); originally in British law, the act of keeping a person against his will, or the wrongful keeping of a person's goods, or other real or personal property. A writ of detainer was a form for the beginning of a personal action against a person already lodged within the walls of a prison; it was superseded by the Judgments Act 1838. In the United States, a detainer in the context of criminal law is a request filed by a criminal justice agency with the institution in which a prisoner is incarcerated, asking the institution either to hold the prisoner for the agency or to notify the agency when release of the prisoner is imminent. The Supreme Court of the United States has held that the Interstate Agreement on Detainers Act (1970) allows for a trial of any untried indictment, information, or complaint within 180 days. However, the prisoner needs to enter a request for final disposition to begin the clock. U.S. Marshals are given the power to issue writs of detainers in 28 U.S.C. 566(c), which is how the federal government interacts with the states to retrieve those being held in state prisons. In Carchman v. Nash, the Supreme Court held that a probation revocation (or parole revocation) is not an "untried indictment, information or complaint" and therefore is not controlled by the Interstate Agreement on Detainer Act's 180-day provision. It also made it clear that a case that where a sentence has already been imposed against the prisoner is not under the 180-day restriction. Unfortunately, this often creates loopholes, where a proceeding still needs to go on in the case with the detainer, but the defendant has already pleaded guilty, and is not eligible to receive a final disposition in the case until his original period of incarceration is over. This creates a situation that is the opposite of what the Interstate Agreement was intended to do: Most states have also enacted laws that create Interstate Commissions, which is usually an agency that creates its own policies and regulations regarding detainers transferring prisoners and probationers across state lines. While the Interstate Agreement on Detainers controls untried cases, Interstate Commission can control whether a person on probation or parole can come to their state to reside. Under the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA), federal U.S. Immigration and Customs Enforcement agents can