In 2000, the FBI began routinely using mitochondrial DNA testing on hair samples obtained from crime scenes and suspects in order to identify who the hair belonged to. But before the bureau had this capability, they were using other methods to try and link hair samples to defendants. These methods relied largely on forensic "experts" who testified about their findings in court - and often helped win a conviction.
But last month, a multi-agency review of FBI cases before 2000 revealed a startling find.
The so-called Microscopic Hair Comparison Analysis Review focused on 28 cases where the bureau's hair analysis experts testified at trial. And in 26 of those cases, investigators found erroneous statements in the trial transcripts that came either from expert testimony or laboratory reports. That's an almost 93% failure rate when it comes to verifying the accuracy of hair analysis tests. The Innocence Project and the National Association of Criminal Defense Lawyers also assisted with the FBI review.
As a result of these findings, the Department of Justice is looking into cases where people may have been convicted based on hair sample analysis data or testimony. The two federal agencies are also reviewing FBI lab protocols, procedures, and practices in an effort to figure out why the bureau continued to produce flawed results. Finally, they're "strongly encouraging" states to conduct their own investigations if they utilized hair analysis experts who were trained by FBI personnel.
This represents yet another example of how "scientific evidence" can be significantly inaccurate despite prosecutors' insistence that the results from these tests are beyond reproach. An experienced criminal defense attorney can help spot these flawed scientific tests, which is why it's so important to retain proper counsel if you are accused of a crime.