What is the test for admissible evidence in federal criminal proceedings?

Rule 402 of the Federal Rules of Evidence states that relevant evidence is admissible in a federal prosecution unless prohibited by the federal constitution, a federal statute, or the federal rules of evidence. "[T]he admissibility of evidence obtained in violation of state law turns on whether a federal right has been infringed, not on the presence or absence of federal involvement at the evidence-gathering stage of an investigation." United States v. Chavez-Vernaza, 844 F.2d 1368, 1373 (9th Cir.1987).