The main issue presented by this cause is whether a police officer’s affidavit in support, of a search warrant is sufficient to show probable cause when that affidavit contains only information received from the personal observations of an unnamed confidential informant and the officer’s avowal that the informant is “reliable.”1
Appellant urges that such an affidavit does show probable cause because, in effect, (1) the affiant’s oath is sufficient to establish, “per se, the credibility of the affiant's source,” and (2) under United States v. Harris (1971), 403 U. S. 573, proof of the informant’s credibility is not required when his “personal observation of criminal activity” supplies the factual basis of the informant’s tip.
Appellant’s first argument is not well taken. The Fourth Amendment requires that magistrates determine probable cause for themselves and that they not rely on the conclusions of the police. Johnson v. United States (1948), 333 U. S. 10, 14; Giordenello v. United States (1958), 357 U. S. 480, 486. Where a magistrate has only the sworn, but otherwise unsupported, assertion of a police officer that the informant is reliable, he has nothing upon which to base his determination of credibility but the officer’s conclusion. Therefore, he cannot credit that unsupported assertion “without abdicating his constitutional function.” Spinelli v. United States (1969), 393 U. S. 410, 416; State v. Karr (1975), 44 Ohio St. 2d 163, 165. This court’s-statement in *179State v. Karr (supra, at page 165), that “[i]t is not sufficient that the affiant swear that his confidant was reliable, when no reason is offered the magistrate in support of that conclusion,” applies to the instant cause.
Appellant’s second argument is that, under United States v. Harris, supra, a showing of the informant’s credibility (where the affiant is not. the informant) is not required when his “personal observation of criminal activity” supplies the factual basis of the informant’s tip.
Although affidavits for search warrants may be based on the hearsay testimony of a confidential unnamed informant, they must, in order to insure that magistrates determine probable cause for themselves, incorporate “a substantial basis for crediting the hearsay.” Jones v. United States (1960), 362 U. S. 257, 269. Under Aguilar v. Texas (1964), 378 U. S. 108, 114, that “substantial basis” must include (1) information about the facts upon which the informant based his allegations of criminal activity, and (2) “some of the underlying circumstances from which the officer concluded that the informant * * * was ‘credible’ or his information ‘reliable.’ ”2 Appellant urges, however, that under United States v. Harris, supra, the informant’s personal observations of criminal activity, which have usually satisfied the first part of the Aguilar test (State v. Karr, supra, at page 165), should also suffice to satisfy the second part of the Aguilar test for probable cause.
Appellant’s interpretation of United States v. Harris, supra, is erroneous.
Four Justices in the Harris case stated, at pages 579-580:
“* * * "While a bare statement by an affiant that he believed the informant to be truthful would not, in itself, provide a factual basis for crediting the report of an unnamed informant, we conclude that the affidavit in the present case contains an ample factual basis for believing the informant which, when coupled with affiant’s own knowledge of the *180respondent’s background, afforded a basis upon which a magistrate could reasonably issue a warrant.”3 (Emphasis added.)
In the present cause the only allegation in support of the informant’s credibility is the officer’s statement that the informant had personally observed the suspect’s criminal activities. Unlike the allegation in Harris that the affiant had personal knowledge of the suspect’s activities or the allegation in State v. Karr, supra, that the informant had given reliable information in the past, the affidavit herein relies upon the informant’s statement to corroborate the informant’s credibility. By failing to provide independent corroboration of the informant’s credibility, the affidavit does not lessen “the chances of a reckless or prevaricating tale” (Jones v. United States, supra, at page 271) and does not give the magistrate an opportunity to make an independent determination of probable cause. The judgment of the Court of Appeals is affirmed.
Judgment affirmed.
O’Neill, C. J., Celebrezze and Sweeney, JJ., concur. Herbert, P. Brown and Locher, JJ., dissent.The affidavit in support of the search warrant stated that a variety of narcotic drugs and the instruments for administering them were to be found at the apartment. In support of that allegation, the affidavit stated: “Information■ received from a confidential and reliable informant who has visited the premises within the past 72 hours and observed the above drugs and instruments for administering these drugs on the premises.”
Crim. R. 41(C) sets out the same test.
Four Justices in the JHarris case also found the fact that the informant’s tip was a statement against interest to be corroborative of the informant’s credibility.