What is the test for a finding of probable cause to search the Whitmore residence?

The role of this court is to determine whether the magistrate had a "substantial basis" upon which to find that probable cause existed to search the Whitmore residence. Illinois v. Gates, 462 U.S. 213, 238 (1983). A magistrate's determination of probable cause is reversed only if clearly erroneous. United States v. Bertrand, 926 F.2d 838, 841 (9th Cir.1991). A reviewing court must "show[ ] deference to the issuing magistrate's determination." United States v. Hernandez, 937 F.2d 1490, 1494 (9th Cir.1991); see also United States v. Fannin, 817 F.2d 1379, 1381 (9th Cir.1987).