Forensic science is a major part of many criminal cases in California and across the nation. Evidence gathered at the scene of the crime is often tested using various methods and the findings are submitted to the court for use in the trial. Yet, in some cases, the scientific results that are sent to the court are not reliable and could be obtained using bad methods. People may be wrongfully convicted of a crime because of this poor evidence. According to the Innocence Project, 45% of cases that were later overturned after DNA evidence proved the innocence of the convicted victim, involved misapplication of forensic science

The misapplication of scientific testing can include any of the following errors:

  • Misleading expert testimony

  • Methods used that have not been scientifically validated

  • Mistakes made by lab technicians, practitioners and/or forensic analysts

  • Used of old methods when new and improved methods are available

Some scientific methods used to convict criminals have been proven to provide inaccurate results, yet some are still used as evidence in court. These include microscopic hair analysis, arson fire analysis, comparative bullet lead analysis, shoe print comparisons and tire tread analysis. Methods that are scientifically valid, such as DNA testing, can be performed improperly, giving bad results. 

According to a California law enacted in 2014, people are able to seek justice in their case if they suspect forensic testing errors have occurred. Some court cases also ask for more than one lab to process evidence in order to minimize the chances of an error.