In Gerstein et al. v. Coe et al., the U.S. Supreme Court ruled that a person arrested without a warrant must promptly be brought before a neutral magistrate for a judicial determination of probable cause, regardless of whether they have been formally charged with an offense through an indictment or information by the prosecutor's office. The case arose from Florida where two individuals were detained on suspicion of robbery but were not given prompt judicial hearings to determine if there was sufficient evidence to hold them in custody pending trial, which violated their Fourth Amendment rights against unreasonable seizures and Fourteenth Amendment due process rights. The court held that while police may arrest someone based on probable cause, continued detention requires further justification via swift judicial assessment.

In the dissenting opinion for Gerstein et al. v. Coe et al., Justice William O. Douglas argued that a person arrested without a warrant should be entitled to a probable cause hearing within 24 hours of arrest, regardless of whether formal charges have been filed by the prosecutor's office or not. He contended that this would protect individuals from being held in custody for an extended period before having their case reviewed by a neutral magistrate, which he believed was unconstitutional under the Fourth Amendment’s protection against unreasonable seizures and detentions. Furthermore, he expressed concern about potential abuses of power if law enforcement agencies were allowed to detain people indefinitely without judicial oversight or review.