In People v. Castillo (80 NY2d 578 [1992]), a defendant moved before the suppression court, pursuant to Mapp v. Ohio (367 US 643 [1961]), to suppress physical evidence seized pursuant to a search warrant, challenging the issuing Judge's determination that probable cause had existed for the search. In response, the People filed a motion for a protective order. The suppression court granted that motion, and authorized the prosecution to withhold the search warrant materials from the defendant. The suppression court then followed the procedure set forth in People v. Seychel (136 Misc 2d 310 [Sup Ct, NY County 1987]), in which it both reviewed the warrant affidavit and took the ex parte testimony of the informant. Upon completion of that procedure, the suppression court concluded that the search warrant had been lawfully issued and denied the motion to suppress. In the Court of Appeals, the defendant in Castillo argued that "regardless of the substantiality of the evidence supporting the warrant or the need for confidentiality, disclosure of the information, if not the identity, of the informant is always required." (People v. Castillo, 80 NY2d, supra, at 580.) The Court of Appeals disagreed and authorized the suppression court to use an ex parte procedure to decide the suppression motion. A defendant thus has no absolute right to disclosure of the facts underlying issuance of a search warrant in connection with his or her contention that probable cause for its issuance was lacking. The issue in Castillo (supra) required the Court of Appeals to balance a defendant's right to participate in the preparation and presentation of his or her suppression motion against the public's need to encourage citizen participation in law enforcement by granting anonymity to informants when necessary to protect their safety. In balancing these considerations, the Court of Appeals, before Castillo, held that suppression courts could lawfully permit the prosecution not to disclose the identity of informants. (See, People v. Darden, 34 NY2d 177, 181-182 [1974].) Castillo broadened Darden to permit, when necessary, withholding all information, when supplied by an informant, underlying the issuance of a search warrant. In expanding Darden, the Court of Appeals stated in Castillo that, in the case before it, "unlike in Darden, none of the purported factual predicates for probable cause [to search] was revealed to the defendant." (Supra, at 584.)