The top U.S. military appeals court has struck down the sexual assault conviction of an airman from Pope Air Force Base in North Carolina, raising questions about the prosecution's use of a "human lie detector."
The "human lie detector" was an Air Force Office of Special Investigations special agent, who testified that he could discern deceit in the defendant, former Airman First Class Michael L. Knapp II.
"Early on in the interview, the accused would not make eye contact with me when we were talking about the sexual intercourse portion," the special agent testified, court records show. "That is indicating to me that there is some form of deception going on."
At another point, the special agent explained that "whenever the accused would speak about the actual incident, while he was looking away the accused would actually get large red sun blotches" on his face.
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Knapp was convicted in a 2010 court martial. He admitted having sexual intercourse with a female airman, but said it was consensual. The prosecution said the female was substantially incapacitated, after having drunk three beers and several shots of liquor over the course of several hours.
In the Jan. 15 decision, the U.S. Court of Appeals for the Armed Forces characterized the special agent's testimony as impermissible, and concluded it prejudiced Knapp's case. Knapp's appellate attorney, Air Force Capt. Isaac C. Kennan, had argued that the special agent's asserted expertise improperly usurped the court martial panel's responsibility for determining credibility, and the appellate court agreed.
The special agent, the court concluded "went too far by declaring that he had been trained to divine a suspect’s credibility from his physical reactions to the questioning."