The McNabb-Mallory referes to a line of cases in the United States Federal Courts which held that a confession obtained during federal custody is inadmissible if the defendant is not promptly produced in court after arrest. The rule was later incorporated into the Federal Rules of Criminal Procedure 5(A) which state that "A person making an arrest within the United States must take the defendant without unnecessary delay before a magistrate judge, or before a state or local judicial officer as Rule 5(c) provides, unless a statute provides otherwise."
In Mallory v. United States, Justice Frankfurter explained the reasoning behind the McNabb-Mallory Rule:
The scheme for initiating a federal prosecution is plainly defined. The police may not arrest upon mere suspicion but only on "probable cause." The next step in the proceeding is to arraign the arrested person before a judicial officer as quickly as possible so that he may be advised of his rights and so that the issue of PROBABLE CAUSE may be promptly determined. The arrested person may, of course, be "booked"by the police. But he is not to be taken to police headquarters in order to carry out a process of inquiry that lends itself, even if not so designed, to eliciting damaging statements to support the arrest and ultimately his guilt.
In theory the McNabb-Mallory rule was repealed when Congress passed the Omnibus Crime Control and Safety Streets Act in 1968. Under this provision the McNabb-Mallory rule was replaced by the "Voluntariness" test in which the period of pre-trial detention became just one factor in determining whether a confession was voluntary. However, courts continue to apply the rule in federal courts.
Critics have stated that the McNabb-Mallory rule created confusion in lower courts as they attempted to interpret the vague standard of unnecessary delay.
- McNabb v. United States, 318 U.S. 332, 63 S.Ct. 608 (1943), Mallory v. United States, 354 U.S. 449, 77 S.Ct. 1356 (1957)
- Federal Rules of Criminal Procedure 5(A)
- Mallory v. United States, 354 U.S. 449, 77 S.Ct. 1356 (1957)
- 42 U.S.C.A. § 3701 et seq.)