The informant, former cadet Eric Thomas, was one of 12 witnesses who testified on behalf of the prosecution in the June 2012 court-martial of classmate Stephan Claxton.
Claxton challenged the findings to the Air Force Court of Criminal Appeals, which in December 2013 upheld the conviction and sentence. He next appealed to the U.S. Court of Appeals for the Armed Forces (CAAF), arguing the defense had the right to know that Thomas was a confidential informant.
The military appeals court will use that information to determine "whether the government's failure to disclose Thomas worked as confidential informant was harmless beyond a reasonable doubt," she said.
"If the evidence [that Thomas was an informant] wasn't turned over, there's an issue as to whether or not there was error," said Greg Rinckey, a military law attorney and former Army JAG.
Working as an informant for the government could give a witness the motive to lie, Rinckey said. "That's grounds for cross-examination by the defense."
Thursday's hearing is expected to last as many as two days, but the appeals court could take much longer to decide whether to affirm Claxton's original disposition, overturn it, modify it or order a new court-martial.
Thomas was expelled from the academy just weeks before he was to graduate for demerits he said he received while working as an informant for the Air Force Office of Special Investigations. That work required him to break cadet policy; when he got into trouble, Thomas said, he was abandoned by OSI.
Thomas' attorney, Skip Morgan, said there were "big errors in the IG report."
"He is looking forward to this opportunity [to testify] because it will be the first time he is on the record with the Air Force" about his work as an informant, Morgan said. "Since the time he was dis-enrolled, he has never really had an audience with anyone from the academy. At least this will establish when he worked as a confidential informant for OSI and what he did."
According to the appellate court's summary of the case, after a night of drinking with friends, including Thomas, Claxton locked himself alone in a dorm room with a woman who had passed out. When Thomas and a second cadet found the room locked, they "pounded on the door" until Claxton opened it slightly.
"Seeing the lights were out, the cadets forced their way in and pulled [Claxton] into the hallway" and a fight ensued, the summary stated. Thomas and the second cadet found the victim unconscious with her jeans unbuttoned and her shirt pulled up to her chest.
She was removed from campus by ambulance.
Though Thomas came to the woman's rescue that night, the statements he gave OSI about the incident served as the basis for a bulk of the demerits against him, Morgan said.
Thomas is appealing his dis-enrollment to the Air Force Board for Corrections of Military Records.