In People v. DeBour, 40 NY2d 210 (1976), the Court of Appeals set forth a four-tiered method for evaluating the propriety of encounters initiated by police officers in their criminal law enforcement capacity. Level One permits a police officer to request information from an individual and merely requires that the request be supported by an objective, credible reason, not necessarily indicative of criminality; Level Two, the common-law right of inquiry, permits a somewhat greater intrusion and requires a founded suspicion that criminal activity is afoot; Level Three authorizes an officer to forcibly stop and detain an individual, and requires a reasonable suspicion that the particular individual was involved in a felony or misdemeanor; Level Four arrest, requires probable cause to believe that the person to be arrested has committed a crime. Probable cause. "exists where the facts and circumstances within their (the officers') knowledge and of which they had reasonably trustworthy information (are) sufficient in themselves to warrant a man of reasonable caution in the belief that' an offense has been or is being committed" Carroll v. United States, 267 U.S. 132, 162, 45 S.Ct. 280, 288, 69 L.Ed. 543, T.D. 3686, 39 A.L.R. 790. See also People v. Oden 36 NY2d 382, 329 N.E.2d 188, 368 NYS 2d 508 (1975) The Court's purpose in People v. DeBour was to provide clear guidance for police officers seeking to act lawfully in what may be fast-moving street encounters and a cohesive framework for courts reviewing the propriety of police conduct in these situations. Having been the basis for decisions in likely thousands of cases over the past 30 years, De Bour has become an integral part of the jurisprudence.