delivered the opinion of the Court:

The court erred in failing to instruct the jury what facts would constitute probable cause for the prosecution. The want "of probable cause is a mixed question of law and fact. As to the existence of the facts relied on to constitute the want of probable cause, that is a question for the jury - but what will amount to the want of probable cause in any case is a question of law for the court. The jury are always instructed hypothetically as to what constitutes probable cause, or the want of it, leaving to them to find the facts embraced in the hypothesis.

As said by Judge Washington in Munns v. De Nemours, 3 Wash. C. C. 31, Fed. Cas. No. 9,926: “In trials of actions of this nature, it is of infinite consequence to mark with precision the line to which the law will justify the defendant in going, and will punish him if he goes beyond it. On the one hand, public justice and public security require that offenders against the law should be brought to trial, and to punishment, if their guilt be established. Courts and juries, and the law officers wffiose duty it is to conduct the prosecutions of public offenders, must in most instances, if not in all, proceed upon the information of individuals : and if these actions are too much encouraged, — if the informer acts upon his own responsibility, and is bound to make *189good his charge at all events, under the penalty of responding in damages to the accused, few will be found bold enough, at so great a risk, to endeavor to promote the public good. The informer can seldom have a full view of the whole ground, and must expect to be frequently disappointed by evidence which the accused only can furnish. Even if he be possessed of the whole evidence, he may err in judgment; and in many instances a jury may acquit, where to his mind the proofs of guilt were complete.” Staples v. Johnson, 25 App. D. C. 155, 160.

Probable cause for a criminal prosecution lies in the existence of such facts and circumstances as would reasonably excite the belief in the mind of an ordinary cautious man, acting on the facts and circumstances within the knowledge of the prosecutor at the time, that the accused was guilty of the crime charged.

And if there be this probable cause, the motives which may have actuated the prosecutor in commencing and carrying on the prosecution are not material.

Where the facts tending to show want of probable cause are in dispute, their existence is for the determination of the jury; but their effect when found is a question for the determination of the court. Spitzer v. Friedlander, 14 App. D. C. 556, 562; Brown v. Selfridge, 34 App. D. C. 242, 247, s. c. 224 U. S. 189, 56 L. ed. 727, 32 Sup. Ct. Rep. 444; Stewart v. Sonneborn, 98 U. S. 187, 189, 25 L. ed. 116; Coleman v. Heurich, 2 Mackey, 189, 197; Boyd v. Cross, 35 Md. 194.

We think the court should have instructed the jury that if they believed that if, at the time of the institution of the prosecution, there were such facts and circumstances as would reasonably excite the belief in the mind of the defendant that the accused was probably guilty of the crime charged, that this would constitute probable cause. If defendant believed that plaintiff had procured the money from Ilooven and Miller upon the representation that the Automobile Pegister had been actually distributed at the time of the collection, and that this fact was untrue, then he would be warranted in inducing Miller to make the complaint.

It was for the jury to say whether the plaintiff: made those *190representations to Miller, and Miller reported the facts to the defendant, who induced him to make the complaint.

Probable cause, too, would exist if all the facts were made known to the prosecuting attorney at the time, and upon them he advised the prosecution.

On the error pointed out the judgment is reversed, with costs, and the cause remanded, with direction to grant a new trial.

Reversed.