What is the test for determining whether a search warrant is valid or invalid?

This court defers to the factual findings of the district court unless clearly erroneous, but questions of application of the law to those facts are reviewed de novo. United States v. McConney, 728 F.2d 1195, 1200-01 (9th Cir.1984) (en banc), cert. denied, --- U.S. ----, 105 S.Ct. 101, 83 L.Ed.2d 46 (1984). The legal questions raised in this appeal are whether the warrantless entry was supported by both probable cause and exigent circumstances; whether the district court erred in refusing to hold a Franks hearing on the accuracy of the warrant application; and finally, whether, if the original entry was illegal, the information obtained tainted the later warrant.

A warrantless search of a home is illegal unless the officers had probable cause and were faced with exigent circumstances. Coolidge v. New Hampshire, 403 U.S. 443, 468, 91 S.Ct. 2022, 2039, 29 L.Ed.2d 564 (1971).