What is the immediate challenge to a search warrant?

Here the instant challenge to the search warrant was to the magistrate's finding of probable cause and to the accuracy and truthfulness of the facts relied on by the prosecution to establish probable cause. Defendant was denied all access to the material facts the prosecution was relying on to establish probable cause. The in camera hearing and review conducted outside defendant's presence in which the trial judge attempted to conjure up various legal and factual challenges to the sealed affidavit will not suffice. Such a procedure "leaves the defendant without an adversary before the court who can not only ascertain that the appropriate challenges are considered but also that the defense argument is vigorously and effectively pursued." (Swanson v. Superior Court, (1989) 211 Cal.App.3d 332, 339, 259 Cal.Rptr. 260.)