Opinion by
Mr. Justice McCollum,The defendant and two other persons were sued as co-conspirators in an executed scheme to extort money from the plaintiff by means of his arrest and detention on the charge of embezzlement. This sufficiently appears from the declaration filed in the case. More than six years after the cause of action arose the declaration was amended so as to remove therefrom the element of conspiracy, and the case was so proceeded in that it resulted in a judgment against the present defendant for the money alleged to have been extorted from the plaintiff, and in a judgment in favor of his co-defendants. It is claimed that the amendment changed the cause of action and deprived the defendants of substantial rights. If the conspiracy was the cause of action and the amendmant substituted for it a new and distinct cause barred by the statute of limitations there would be obvious merit in the defendants’ contention. But the essence of the complaint in the declaration was the extortion, and the amendment was not necessary to authorize or sustain the judgment appealed from. This being so the defendants were not in any manner prejudiced by the amendment. It did not introduce a new cause of action nor contribute to the result complained of. The case as presented by the pleadings before the amendment was allowed was clearly within the principle of Laverty v. Vanarsdale, 65 Pa. 507, in which it was held that where an action is brought against more than one for a wrong done, in order to recover against all a com*492bination or joint act of all must be proved, but if it turns out on the trial that one only was concerned, the plaintiff may recover as if such one had been sued alone, and in such case the conspiracy is nothing as to sustaining the action, the foundation being the actual damage done to the plaintiff. To the same effect is Collins v. Cronin, 117 Pa. 35, in which it was held that in an action against two or more in case in the nature of a conspiracy, if the tort be actionable, whether committed by two or more, recovery may be had against but one, but, if the tort be actionable only when committed under an unlawful conspiracy of two or more, recovery may not be had unless the unlawful conspiracy be established. In the case before us, as in Laverty v. Vanarsdale, the tortious act complained of was “ capable of being performed by one defendant alone.” For these reasons the defendant’s eleventh point was inapplicable, and the answer thereto, although technically erroneous, furnishes no ground for reversing the judgment.
There was probable cause for the arrest of the plaintiff for the crime with which he was charged in the information, and the warrant for it was regular upon its face. The arrest, therefore, considered by itself, afforded no ground for an action for malicious prosecution. This much was conceded by the learned referee, who nevertheless found that the arrest was made for the purpose of extortion, and that the moneyobtained by it was paid under duress. As these findings appear to be warranted by the evidence the case must be disposed of upon them. To constitute duress by imprisonment the latter must be unlawful, or there must be an abuse of or an oppression under lawful process or legal detention: 6 Am. & Eng. Ency. of Law, 62, and cases there cited. If there is an arrest for a just cause but for ah unlawful purpose the party arrested if he is thereby induced to enter into a contract may avoid it as one procured by duress: Baker v. Morton, 12 Wall. (U. S.) 150. “Though a person is arrested under a legal warrant and by a proper officer yet if one of the objects of the arrest is thereby to extort money or enforce the settlement of a civil claim such arrest is false imprisonment by all who have directly or indirectly procured the same or participated therein for any such purpose ; and a release or conveyance of property obtained by means of such arrest is void:” Hackett v. King, 6 Allen, 58. *493The principles enunciated in the citations made are in accord with the decisions of this court: Prough v. Entriken, 11 Pa. 85; Schofield v. Ferrers, 47 Pa. 194; Schmidt v. Weideman, 63 Pa. 173; Mayer v. Walter, 64 Pa. 285; Work’s Appeal, 59 Pa. 445. The law does not countenance the employment of criminal process for the collection of debts and the enforcement of civil liabilities. If there is probable cause for a criminal prosecution and it is instituted and maintained for a lawful purpose, the acquittal of the accused does not give him an action against the prosecutor. But if there is just cause for the prosecution and it is resorted to for an unlawful purpose the prosecutor will not be permitted to acquire anything by it. These well settled principles are applicable to the facts found by the learned referee in the case at bar. The plaintiff was arrested on the charge of embezzlement and for the purpose of extorting money from him. The prosecution was abandoned when the purpose of it was accomplished. He parted with his property while under duress by imprisonment and threats, and his right to recover it from the wrongdoer cannot under the circumstances shown be successfully questioned. We think, too, that as the act of which he complains was obviously unlawful and tortious he may recover the property obtained by it in this form of action.
The specifications of error are overruled.
Judgment affirmed.