The district court did not err in dismissing the plaintiffs’ suit against a doctor for his actions as an expert witness in administrative hearings for the Federal Black Lung Program. In this RICO litigation, the doctor was entitled to the Witness Litigation Privilege, which protects witnesses who testify in judicial and quasi-judicial proceedings from later civil liability. Once the privilege attaches, it bars all civil claims stemming from the witness’s participation before a tribunal. Neither expert witnesses who appear voluntarily nor those who engage in deliberate fraud are entitled to less protection than other witnesses. Judge King dissented.