What is the test for establishing a conspiracy against a defendant?

With respect to the conspiracy claim, the government only had to prove the existence of an agreement to engage in criminal activity in which one or more overt acts in furtherance of that agreement had been committed. See United States v. Hernandez, 876 F.2d 774, 777 (9th Cir.), cert. denied, 110 S.Ct. 179 (1989). "If the government proves the existence of a conspiracy, the defendant[ ] need only have a slight connection to it." Id. at 779. Presence may support an inference of culpability "when viewed in context with other evidence." Id. (quoting United States v. Penagos, 823 F.2d 346, 348 (9th Cir.1987)).