Fensterer (D) was convicted of murdering his fiancé, Stephanie Swift. The case was based on circumstantial evidence based on the theory that D strangled Swift with a cat leash. The state established this by proving that two hairs found on the leash were similar to Swift's and that one of the hairs had been forcibly removed. An FBI special agent testified that one of the hairs had been forcibly removed but had no special knowledge on just how the hairs were forcibly removed. On cross, the agent was unable to recall the method he had employed to determine how he had concluded that the hairs were forcibly removed. D offered his own expert who agreed that the hairs were similar to Swift's and based on a prior phone call with the FBI special agent he proceeded to challenge that agent's conclusion that the hair had been forcibly removed in that a follicular tag could attach to hairs that naturally fall out. D was convicted and appealed based on the fact that the special agent's testimony could not be adequately cross-examined unless he had remembered the test he used to determine that the hair had been forcibly removed.