Juries in California and around the country tend to find evidence provided by forensic experts to be extremely compelling, and criminal defendants are often convicted based largely on their testimony. Juries may be surprised to learn that the science supporting criminal forensic procedures is far from perfect. A team of researchers from the U.S. National Academy of Sciences looked into the way forensic evidence is gathered and processed in the United States, and they discovered problems with virtually every technique they scrutinized.
The NAS study, which was published in 2009, highlighted deficiencies in the way forensic scientists analyze fibers, hairs, fingerprints and bite marks. However, its most scathing criticism was reserved for blood pattern analysis. This is a technique forensic scientists use to determine what happened at a crime scene based on blood splatters, smears, and drips. The NAS researchers concluded that the science behind BPA is less than rigorous, and its practitioners lack accreditation and training.
According to the study, BPA experts are not required to meet strict educational standards and provide subjective opinions that have little scientific merit. The researchers concluded that BPA, as a discipline, was shrouded in uncertainty. These criticisms were echoed in 2016 by a panel of scientists from the president's Council of Advisors on Science and Technology and in 2018 by experts from the Texas Forensic Science Commission.
Experienced criminal defense attorneys may be familiar with the uncertainty surrounding forensic techniques, and they could call on experts of their own to inform juries about studies that have raised questions about these methods. Lawyers could also make these points during plea negotiations when the cases against their clients are based on forensic evidence. In these situations, attorneys could urge prosecutors to reduce the charges against their clients in return for quick resolutions and successful outcomes.