What authority exists for the proposition that once the trial court has ruled that a prima facie case has been made and that the burden has shifted to the prosecution?

Second, there is authority for the proposition that once the trial court has ruled, expressly or by implication, that a prima facie case has been made and that the burden has shifted to the prosecution, the court may not then "return to the screening process. The sole issue then pending is the adequacy of the justifications." (People v. Granillo (1987) 197 Cal.App.3d 110, 122, 242 Cal.Rptr. 639; see also People v. Gonzalez, supra, 211 Cal.App.3d 1186, 1198, 259 Cal.Rptr. 870.)