What is the test for determining whether there is sufficient circumstantial evidence to sustain a conviction for sexual assault?

Our role is to view the evidence in the light most favorable to the prosecution and determine whether any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt. United States v. Federico, 658 F.2d 1337, 1343 (9th Cir. 1981); United States v. Bailey, 607 F.2d 237, 243 (9th Cir. 1979), cert. denied, 445 U.S. 934, 100 S.Ct. 1327, 63 L.Ed.2d 769 (1980). The question to ask is not whether the evidence excludes every hypothesis except guilt, but whether the trier of fact could reasonably arrive at its conclusion. All reasonable inferences must be drawn in favor of the Government, and circumstantial evidence is sufficient to sustain a conviction. Federico, 658 F.2d at 1343-44.