Is fear of retaliation sufficient to prevent a witness from testifying in a grand jury trial?

We review the district court's finding of contempt for abuse of discretion. In re Grand Jury Proceedings (Doe), 801 F.2d 1164, 1167 (9th Cir.1986) (per curiam). "No federal court in a reported decision has held that fear of retaliation is sufficient reason to refuse to testify. We ... follow the reported decisions of those courts which have already held that fear of physical harm does not excuse a witness from testifying." In re Grand Jury Proceedings, 914 F.2d 1372, 1375 (9th Cir.1990) (quoting Dupuy v. United States, 518 F.2d 1295 (9th Cir.1975).