What is the test for obtaining a search warrant for an alleged drug dealer based on a tip from a confidential informant?

Before a search warrant may issue, evidence must be submitted establishing probable cause that contraband or evidence of a crime will be found in the place to be searched. United States v. Depew, 8 F.3d 1424, 1428 (9th Cir.1993). Magistrates must examine the "totality of the circumstances" set forth in the affidavit to determine whether probable cause exists. The circumstances that a magistrate may consider include an informant's reliability and basis of knowledge. However, a deficiency in one of these elements may be compensated for by a strong showing as to the other, or by other indicia of reliability. One indicium of reliability is the corroboration of details of an informant's tip by independent police work. United States v. Ayers, 924 F.2d 1468, 1478 (9th Cir.1991); see Illinois v. Gates, 462 U.S. 213, 233, 241, 103 S.Ct. 2317, 2329, 2334, 76 L.Ed.2d 527 (1983).