One case that involved ambiguity was the exoneration of Steven Avery. The Innocence Project’s description, which conflicts with the one on the National Registry of Exoneration’s website, says that “[a] state forensic examiner testified that a hair recovered from a shirt of Avery’s was consistent with Beerntsten’s hair [victim].” According to a transcript of the cross-examination of the forensic examiner who conducted the microscopic hair analysis, the examiner located three head hairs on a shirt seized from Avery and concluded that two of the head hairs were inconsistent with the victim’s hair. The examiner concluded that the third questioned hair found on the shirt was “consistent” with the victim’s hair; however, the examiner then explained that a microscopic hair comparison is not a method that can be used to identify the actual source of a questioned hair.
Here are portions of the cross-examination:
Q: Ms. Culhane, is it possible to prove identification by hair analysis?
Q: Is the hair of many people consistent with each other?
Q: Is it unusual for hair from different people to be consistent with each other?
A: No, it’s not.
Q: For example, is it unusual for the hair of white Caucasians to be consistent with each other?
Q: If, for example, you took hair from ten different people, would it be unusual to get consistencies between the hair[s] from those people?
Q: It would be usual, wouldn’t it?
A: Yes, it would be.
Q: Other than the standards that you have spoken of, did you have any other standards?
A: I did have a pubic hair.
Q: But, of head hair, did you have any standards other than the ones you testified about?
A: No, sir.
Q: You had no standards that were purportedly from hospital or ambulance personnel?
A: No, sir.
Q: Do you have any standard purportedly from the husband of the victim?
A: No, sir.
Q: Any standard purportedly from a Diane Messman or John Gould?
Q: Any standard from any of Mr. Avery’s children?
A: No, sir.
Q: The hair that you found from the white sheet that was inconsistent with the victim’s hair, did you analyze it to determine if it was consistent with Mr. Avery’s?
Q: The hair that was found on the brown T-shirt, did it have any distinguishing characteristics?
A: By distinguishing, do you mean unusual characteristics?
Q: Isn’t that what makes it possible for you to find a hair inconsistent with another, that it has some distinguishing characteristic?
A: Well, by distinguishing, if you mean characteristics specific to that hair, yes, it does. It has nothing out of the ordinary or unusual that would make it rare or anything like that.
Q: What is it about the hair that makes it possible to distinguish it from other hair?
A: The structural features. By that, I mean the presence of a medulla, which is the center portion of the hair, the color, the diameter.
Q: Are any of those structural characteristics rare?
Q: Are they common?
Q: Are you able to give the opinion as to the probability of the hair from the brown T-shirt being from the same source as the D-12 sample?
A: I don’t understand what you mean by --- I ---
Q: The hair on the brown shirt, that’s consistent with the D-12 standard. Can you give an opinion as to the probability whether they’re from the same source?
Q: All you can say is that it’s not impossible that they’re from the same source, isn’t that correct?
A: That’s right.
Q: And if you were given other standards and compared it against that hair from the brown T-shirt, it could be consistent with some or all of those, isn’t that right?
A: It’s conceivable. Yes.