What standard of review is required for a motion for an evidentiary hearing?

We are unable to find a case directly on point for a standard of review for this motion. However, we review a denial of a motion for an evidentiary hearing regarding allegations of jury misconduct for abuse of discretion. United States v. Navarro-Garcia, 926 F.2d 818, 822 (9th Cir.1991). "Unless the court is able to determine without a hearing that the allegations are without credibility or that the allegations if true would not warrant a new trial, an evidentiary hearing must be held." Id.