Probable cause is a reasonable belief of the police officer in the guilt of the suspect, based on the facts and information prior to the arrest. For instance, a warrantless arrest may be legitimate in situations where the police officer has a reasonable belief that the suspect has either committed a crime or is about to commit a crime. The police officer might also arrest the suspect to prevent the suspect’s escape or to preserve evidence. However, a warrantless arrest may be invalidated if the police officer failed to demonstrate exigent circumstances and probable cause.
The right to make warrantless arrests are commonly defined and limited by statutes subject to the due process guaranty of the U.S. Constitution. The suspect arrested without a warrant is entitled to prompt judicial determination generally made in 48 hours.
See, e.g. Maryland v. Shatzer, 130 S.Ct. 1213 (2010).
[Last updated in June of 2022 by the Wex Definitions Team]