Can a person secure an entity&#39;s former employee to act as an expert witness against them?
<p>In federal court, is there any ethical or evidentiary rule that prohibits a person from using that entity's former employee as an expert witness against them?</p>

<p>For context, I would like to use a former jail correctional psychiatrist as an expert witness to give testimony that would help establish that said jail doesn't conform to constitutional standards of mental health care.</p>

<h2>An expert witness must be independent</h2>

<p>A former (or current) employee of a party is not independent. The court may accept their independence if the relationship was decades in the past but not otherwise.</p>

<p>If you want the said psychologist to testify about things that happened in the jail they aren’t acting as an expert witness anyway - they are acting as a witness of fact.</p>

united-states federal-courts professional-ethics rules-of-evidence