Serial: Why Jay’s Testimony Is Not Credible Evidence of Adnan’s Guilt

In a later post, I plan on expanding further on Adnan’s cell phone records and the related witness testimony, and discussing what we can reconstruct about Hae’s murder from the existing evidence. This post, however, is not about the evidence that we have. It’s about the evidence that we don’t have — and that’s evidence that Jay is telling the truth about Adnan’s involvement in Hae’s death.

Now, it’s possible that Adnan is still guilty of Hae’s murder, and that the state managed to get the right guy, even if they didn’t have much to go on. Possible. The fact that Jay is a completely incredible witness is not evidence that Adnan is innocent. But that doesn’t change the fact that the state’s evidence was based entirely on the uncorroborated testimony of a self-acknowledged liar with a motive to falsely incriminate Adnan.

The state has itself acknowledged that Jay was the alpha and the omega of its case against Adnan. At trial, the prosecutor told the jury, “Let’s talk about Jay [ ] because, clearly, this case hinges on his testimony” (Brief of Appellant at 40). But while the prosecution then went on to continually assert, at every opportunity, that Jay was a “credible” witness, there was simply no objective basis for believing that Jay was likely to tell the truth when he testified at Adnan’s trial.

I’m not trying to be hyperbolic here, or to exaggerate for effect. I know that’s a pretty expansive claim to make. But it also happens to be accurate. We know that Jay had every motivation to lie and no motivation to the tell the truth; had a demonstrated history of lying when it was to his own advantage; and lacked corroborating evidence in support of his claims. Even assuming that Adnan is guilty of Hae’s murder, there was still no objective reason to find Jay’s testimony on that point to be credible.

How can a thing like that be evaluated? Well, the credibility of a witness’s testimony — that is, roughly speaking, the testimony’s evidentiary value — is judged in reference to four basic factors. Those factors are sometimes formulated in different ways, or split into additional categories, but they  can be summarized as the following:

  1. Inherent Credibility. A witness’s general character for truthfulness and honesty.
  2. Bias or Interest. A witness’s motive to lie in a particular circumstance.
  3. Inconsistent Statements. Whether a witness’s statements have been internally consistent.
  4. Corroboration by Other Evidence. A witness’s credibility is enhanced when his testimony matches known evidence.

With those factors in mind, how does Jay’s testimony stack up?

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