Randy Lightly (defendant) and Clifton McDuffie, inmates at Lorton Reformatory, were investigated regarding their involvement in the stabbing of Terrance McKinley, a fellow inmate. The grand jury indicted Lightly but not McDuffie because a court appointed psychiatrist found McDuffie to be criminally insane and incompetent to stand trial. At Lightly’s trial, McKinley, two other inmates and McKinley’s doctor testified that Lightly and McDuffie cornered McKinley in his cell and repeatedly stabbed him. The testimony indicated that the bad cut on Lightly’s hand was the result of this altercation. Lightly, whose testimony was corroborated by the testimony of three other inmates, said that he saw McDuffie stabbing McKinley and when he stepped in to stop McDuffie, McDuffie slashed Lightly’s hand. Lightly sought to have McDuffie testify. McDuffie, who was confined to a mental hospital, would have testified that he was the only person attacking McKinley. McDuffie’s treating physician testified that McDuffie’s memory was sufficient, that he understood the oath and was able to testify about what he saw. After declining to hear McDuffie’s proffered testimony in camera, the court ruled that McDuffie was not competent to testify because he had been found criminally insane and incompetent to stand trial and suffered from hallucinations. Lightly was convicted of assault with intent to commit murder and appealed his conviction claiming that the trial court erred in disqualifying McDuffie as a witness under Federal Rule of Evidence (FRE) 601.