PROBABLE CAUSE - A reasonable belief that a person has committed a crime. The test the court of appeals employs to determine whether probable cause existed for purposes of arrest is whether facts and circumstances within the officer's knowledge are sufficient to warrant a prudent person to believe a suspect has committed, is committing, or is about to commit a crime. U.S. v. Puerta, 982 F.2d 1297, 1300 (9th Cir. 1992). In terms of seizure of items, probable cause merely requires that the facts available to the officer warrants a "man of reasonable caution" to conclude that certain items may be contraband or stolen property or useful as evidence of a crime. U.S. v. Dunn, 946 F.2d 615, 619 (9th Cir. 1991), cert. Denied, 112 S. Ct. 401 (1992).
It is undisputed that the Fourth Amendment, applicable to the states through the Fourteenth Amendment, prohibits an officer from making an arrest without probable cause. McKenzie v. Lamb, 738 F.2d 1005, 1007 (9th Cir. 1984). Probable cause exists when "the facts and circumstances within the arresting officer's knowledge are sufficient to warrant a prudent person to believe that a suspect has committed, is committing, or is about to commit a crime." United States v. Hoyos, 892 F.2d 1387, 1392 (9th Cir. 1989), cert. denied, 489 U.S. 825 (1990) (citing United States v. Greene, 783 F.2d 1364, 1367 (9th Cir. 1986), cert. denied, 476 U.S. 1185 (1986)).
When there are grounds for suspicion that a person has committed a crime or misdemeanor, and public justice and the good of the community require that the matter should be examined, there is said to be a probable cause for, making a charge against the accused, however malicious the intention of the accuser may have been. And probable cause will be presumed till the contrary appears.
In an action, then, for a malicious prosecution, the plaintiff is bound to show total absence of probable cause, whether the original proceedings were civil or criminal.