Probable cause to arrest is an exceedingly difficult concept to objectify.' The traditional definition was stated in Beck v. Ohio as follows: [W]hether at that moment the facts and circumstances within their knowledge and of which they had reasonably trustworthy information were sufficient to warrant a prudent man in believing that the petitioner had committed or was committing an offense. Judicial opinions frequently manifest empathy with the policeman's plight in attempting to apply this vague standard. While the standard does not mean that the arresting officer must have evidence that would satisfy a fact finder of guilt beyond a reasonable doubt, probable cause is clearly more than "mere suspicion."' It is axiomatic that probable cause can never be established by the fruits of illegal search, and the good faith of the officer can add nothing to facts that otherwise do not reach the level of probable cause. Nevertheless, police, by virtue of their experience and expertise, may be able to identify certain activities as indicative of criminal behavior that might not appear so to a judge or layman. The viewpoint of an experienced officer, therefore, may be taken into account in determining the presence of probable cause.
Joseph G. Cook,
Probable Cause To Arrest,
24 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol24/iss2/4