What is the standard of review for a motion alleging conspiracy to pervert the course of justice?

"On a challenge to the sufficiency of the evidence, the standard of review is whether there is substantial evidence to support the conviction. The court must view the evidence in the light most favorable to the government. If any rational jury could find the essential elements of the crime beyond a reasonable doubt, the conviction must be affirmed." United States v. Luttrell, 889 F.2d 806, 809 (9th Cir.1989).

"[C]onspiracy is established by an agreement to engage in criminal activity, one or more overt acts taken to implement the agreement, and the requisite intent to commit the substantive crime." Id. "The agreement need not be explicit; it may be inferred from the defendant's acts pursuant to a fraudulent scheme or from other circumstantial evidence." United States v. Cloud, 872 F.2d 846, 852 (9th Cir.), cert. denied, 110 S.Ct. 561 (1989). "An inference of the existence of a conspiratorial agreement may also be drawn if there be concert of action, all the parties working together understandingly, with a single design for the accomplishment of a common purpose." Id.