What is the standard of review for a finding of exigent circumstances 3?

Our standard of review for the district court's finding of exigent circumstances ³ is governed by our prior decision in United States v. McConney, 728 F.2d 1195 (9th Cir.) (en banc), cert. denied, 469 U.S. 824, 105 S.Ct. 101, 83 L.Ed.2d 46 (1984). The trial court's findings as to the underlying facts and the credibility of witnesses are reviewed under the clearly erroneous standard. Id. at 1200. The selection of the applicable law and the application of that law to the facts is reviewed de novo. Id. at 1201.