Hair Analysis Under a Microscope

Over the weekend, the Washington Post ran a story that begins as follows:

The Justice Department and FBI have formally acknowledged that nearly every examiner in an elite FBI forensic unit gave flawed testimony in almost all trials in which they offered evidence against criminal defendants over more than a two-decade period before 2000.

Of 28 examiners with the FBI Laboratory’s microscopic hair comparison unit, 26 overstated forensic matches in ways that favored prosecutors in more than 95 percent of the 268 trials reviewed so far, according to the National Association of Criminal Defense Lawyers (NACDL) and the Innocence Project, which are assisting the government with the country’s largest post-conviction review of questioned forensic evidence.

In a nutshell, analysts “systematically testified to the near-certainty of ‘matches’ of crime-scene hairs to defendants, backing their claims by citing incomplete or misleading statistics drawn from their case work,” while “[i]n reality, there is no accepted research on how often hair from different people may appear the same.”

The story emphasizes that there may be other evidence of guilt in many of the cases, and that the cases that have been reviewed so far are only a small fraction of the cases that have been identified as candidates for review.

I couldn’t find online the FBI/USDOJ formal acknowledgement referenced in the article. This FBI web page notes the existence of the review and states that “microscopic hair comparison analysis is a valid scientific technique still conducted by the FBI Laboratory” and that “[t]he science of microscopic hair comparisons is not the subject of the review.”

The New York Times has a ten-minute documentary explaining hair analysis and the limits thereof. A former FBI analysis quoted extensively in the video found that 11% of seeming “matches” were shown by DNA not to be matches.

DNA testing has supplemented hair analysis in recent years. As noted above, the federal review concerns “a two-decade period before 2000.” My understanding is that the review ends then because in recent years, hair analysis hasn’t normally been done by itself. Instead, it’s typically done in conjunction with DNA testing, which is much more reliable.

What about North Carolina? The cases reviewed so far don’t include any defendants in North Carolina’s state courts, but do include three federal defendants from North Carolina, as noted in this chart. The lack of North Carolina state cases may be due to the fact that the SBI Lab, as it was then known, conducted hair analysis itself, obviating the need for FBI involvement. Local labs also conducted hair analysis in some North Carolina cases.

This testimony was sometimes admitted in criminal trials. My quick review of published cases suggests that SBI analysts were typically rather cautious in their testimony. For example, in State v. Pratt, 306 N.C. 673 (1982), an SBI analyst testified only that “pubic hair found on [the victim and] . . . pubic hair samples obtained from defendant . . . [were] ‘microscopically consistent’” but did not conclusively identify the perpetrator of the crime.

Some local analysts may have been less restrained. For example, in State v. Suddreth, 105 N.C. App. 122 (1992), a local lab analyst testified that the defendant’s hair and hair found at crime scene “exhibited all the same macroscopic and microscopic characteristics”; that the hair found at the crime scene was “quite likely to have originated from [the defendant]”; and that only one in one thousand individuals have hair matching the observed characteristics. The court of appeals ruled that the testimony was properly admitted, stating that “[o]ur courts have liberally permitted the introduction of expert testimony as to hair analysis when relevant to aid in establishing the identity of the perpetrator,” though cautioning that such evidence is not conclusive evidence of identity. However, the court subsequently ruled in State v. Bridges, 107 N.C. App. 668 (1992), a case involving the same analyst that had testified in Suddreth, that it was improper to admit statistical estimates such as one in one thousand, as there was insufficient foundation for such testimony.

North Carolina review underway. The Post articles states that “Texas, New York and North Carolina authorities are reviewing their hair examiner cases, with ad hoc efforts underway in about 15 other states.” My understanding is that the State Crime Lab has identified several thousand hair examinations conducted by the lab prior to the advent of DNA testing, and that the North Carolina Center on Actual Innocence is reviewing those cases to determine whether they resulted in convictions, and if so, whether misleading testimony was given and whether physical evidence exists that could be retested. I don’t know whether hair analysis conducted by local labs is within the scope of the project, and I don’t know how far along the project is. Those who are involved with the review are certainly invited to comment if they wish to do so.

2 thoughts on “Hair Analysis Under a Microscope”

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.