One of the keys to Byron Case's conviction in State v. Case was an audiotaped conversation between Case and Kelly Moffett, his ex-girlfriend and eyewitness in the trial. Case and many of his supporters believe that this represented a miscarriage of justice.

The specific incident in question is as follows:

Kelly Moffett telephoned Byron Case late on the night of June 5, 2001 at the behest of the Jackson County Sheriff's Department, attempting to engage him in conversation about the murder with the story that she had again been contacted by investigators, and that she could no longer remember the alibi to which Moffett and Case had agreed. The conversation had progressed for more than three minutes, with the main subject being what Moffett should say to investigators, when Moffett made the direct reference to Case being the murderer:¹

      MOFFETT:  [The police] called me while I was in rehab, they showed up out there. Yeah, I don’t understand, 
                like seriously, what all went on or whatever, and I seriously, I hate to say this, but why, 
                seriously, why did you have to kill her? What was the whole fucking big deal? Could you 
                explain that to me?

      CASE:     [no response]

      MOFFETT:  Because I don’t get it. Seriously. Justin’s dead for no reason, [Anastasia’s] dead for no reason, 
                it’s all just fucked up. And for some reason they’re talking to me, because you won’t talk. So 
                I’m fucked. And it makes me look horrible because everybody already knows that I’m a fucking 
                crack-head, and that I’m a coke-head, that I’m an alcoholic so I don’t remember shit. And if I 
                tried to talk to them, nothing’s going to add up.

      CASE:     [no response]

      MOFFETT:  So, I mean, if you could, seriously, explain to me as to why you actually felt the need to 
                kill her, than that would really help me feel better about the whole fucking thing.

      CASE:     [no response]

      MOFFETT:  I mean, was there, seriously, any reason to all of this?

      CASE:     We shouldn’t talk about this.

      MOFFETT:  Why?

      CASE:     Probably because we shouldn’t talk about this.

According to Black's Law Dictionary, a tacit (or implied) admission is "an admission reasonably inferable from a party's action or statement, or a party's failure to act or speak." It means that a jury can reasonably take a defendant's failure to deny a direct accusation to be an admission in itself.

In this conversation, in which both Case and Moffett were discussing the investigation into Anastasia's murder, and specifically Kelly's claim that police were wanting to question her again about it, Byron Case talked with her quite straightforwardly and coherently, and gave her direct advice on dealing with police questions. However, when Moffett made three clear and direct accusations that Case was himself Anastasia's killer, he suddenly became evasive, choosing not to respond to her questions, and then deliberately steering her away from the subject by saying "We shoudn't talk about this". The jury in State v. Case was allowed, but not required to consider Case's silence when directly accused of murder to be a tacit admission. Having the choice, the jury considered Case's silence and evasion of the question to be tantamount to an admission of guilt.

Unknown to the jury, Case had much earlier communicated to Anastasia's family an incident in which he claimed to have been accosted by an individual he couldn't identify, who made a much less direct accusation against him, and to whom he repondeded much more directly.² For all of Case's excuses about why he didn't respond to Moffett's accusations, he has never explained how he could evade one from someone who knew him after having so directly and strongly reacted to a less direct remark from someone he did not know.