Three cases were tried before one jury by an agreement of counsel; a nonsuit was entered which the court subsequently refused to lift. Separate appeals were taken, and argued together in this court. The actions were trespass, for false imprisonment and malicious prosecution. There is nothing in this record to connect the defendant with the institution of the proceedings before the magistrate, through which the three plaintiffs were arrested. The converse is clearly shown, that he did' not direct or know anything in regard to it until this suit was begun. Ho authority of the agent to have the plaintiffs arrested was shown, nor can any be inferred from the admitted facts. Undoubtedly a principal may be *548held liable for the act of his agent in instituting a malicious prosecution. But the act of the agent becomes that of the principal only where expressly authorized, or where his authority to act may be fairly inferred from the nature and scope of the employment: Markley v. Snow, 207 Pa. 447. It is just as apparent, as developed by the plaintiff’s testimony, that there was probable cause for their arrest; they defied the direction of the defendant’s agent to vacate the premises which had been regularly delivered to him by the sheriff in pursuance of a writ of habere facias, regular on its face, and unchallenged in any way; they were given a reasonable time to withdraw peaceably and had no legal right to remain. We held in Scott v. Dewey, 23 Pa. Superior Ct. 396, that where in an action for malicious prosecution the plaintiff’s own evidence shows probable cause, offers of evidence made in support of the allegation of malice are properly rejected as immaterial, and that the burden of proof in such a case is on the plaintiff, both as to malice and want of probable cause. If the admitted facts amount to probable cause, a verdict for the defendant should be directed by the court. What is probable cause and whether it existed under an admitted and clearly established state of facts, is a question of law for the court: Robitzek v. Daum, 220 Pa. 61.

The nonsuit was properly entered and the judgment is affirmed.