What is the role of a magistrate in determining probable cause in a criminal case?

The magistrate is called upon only to determine whether the factual showing is sufficient to establish probable cause to believe the defendant committed a felony. (People v. Slaughter (1984) 35 Cal.3d 629, 636-637; Pen. Code, 866, subd. (b).) "'Within the framework of his limited role, . . . the magistrate may weigh the evidence, resolve conflicts, and give or withhold credence to particular witnesses. In other words, in assisting him in his determination of "sufficient cause," the magistrate is entitled to perform adjudicatory functions akin to the functions of a trial judge. Yet the proceeding is not a trial, and if the magistrate forms a personal opinion regarding the guilt or innocence of the accused, that opinion is of no legal significance whatever in view of the limited nature of the proceedings.'" (People v. Slaughter, supra, at p. 637, citations omitted.)

"In short, the magistrate is not a trier of fact. He does not decide whether defendant committed the crime, but only whether there is '"some rational ground for assuming the possibility that an offense has been committed and the accused is guilty of it."' If the record shows strong and credible evidence of defendant's guilt, the magistrate may reasonably assume the possibility of his guilt. Thus in many cases he will not find it necessary to resolve all conflicts in the evidence, in order to find probable cause to hold the defendant for trial. The magistrate's power to decide factual disputes exists to assist him in his determination of sufficient cause; if he can determine that issue without resolving factual conflicts, he may do so." (People v. Slaughter, supra, 35 Cal.3d at pp. 637-638, citations and fn. omitted.)