Probable cause is what is needed for an arrest, different from reasonable suspicion to stop, frisk, hold at the scene, or conduct a brief investigation; also, different from a mere encounter or pedestrian stop (ped stop). Probable cause is defined in large part that the person arrested had or was committing a crime, or that illegal items were at the place of the arrest, like a marijuana or cocaine on the table. The standard for “committing a crime” is not what a police officer would think, rather what an objectively prudent person would think. The police cannot use police intuition to create their own probable cause, they must analyze the situation as a regular citizen.
Also, the police need specifics, not a general idea. If a description of a person is given, more then just race, height and weight is needed, a fuller description is required, and the person must match the description given. Further, when the police find the person who does match the specific description, no probable cause for arrest exists until after an investigation is completed at or near the scene, only reasonable suspicion. The purpose of the investigation is to ensure the person stopped is the person for whom the police have probable cause to make the arrest. A great example is Hayes v. Florida, 470 U.S. 811 (1985), where the suspect was transported to the police station for finger printing and analysis to determine if he was the person who was wanted. The Supreme Court held, taking someone to the station is an arrest requiring probable cause. The most the police can do in this situation is detain the person on the scene, and have the finger print people come out to the scene–a reasonable suspicion analysis.