When faced with conflicting expert opinions during an Article 32 preliminary proceeding, the Preliminary Hearing Officer (PHO) must act as a preliminary gatekeeper and fact-finder. The PHO’s role is not to definitively decide which expert is correct, but to determine if the government’s expert evidence is credible enough to support a finding of probable cause.
First, the PHO will allow both the government and the defense to present their respective expert witnesses. Each side will conduct a direct examination to lay out their expert’s qualifications, methodology, and conclusions. The opposing counsel will then have the opportunity to conduct a vigorous cross-examination, challenging the expert’s credentials, the reliability of their methods, and the basis for their opinion.
The PHO must listen to this conflicting testimony and assess the relative credibility and persuasiveness of each expert. The PHO will consider factors such as the expert’s experience, the clarity of their testimony, and the soundness of their reasoning. The ultimate question for the PHO is whether the government’s expert testimony, even in the face of a defense challenge, is sufficient to establish a reasonable belief that the accused committed the offense.
In the final report, the PHO should summarize the conflicting expert opinions and explain why they found one to be more persuasive for the purpose of determining probable cause. The PHO is not declaring one expert “right” and the other “wrong” for all time. They are simply concluding whether the government has presented enough credible expert evidence to justify sending the case to trial, where a panel of members will have the ultimate responsibility of resolving the conflict.