Evidence obtained at the scene of the crime, on the suspect or on the victim is processed using a number of forensic methods. This information is then presented to the court, usually by a scientific expert. The way in which the evidence is collected, processed, tested and then presented to the court can have a major impact on whether a person is convicted of the crime. 

According to the Innocence Project, more than 354 people were released from prison after DNA evidence proved that they were innocent of committing a crime. Of these cases, 45% involved the misapplication of forensic science. 

Improper testing of evidence 

One way forensic evidence can cause the wrong person to be convicted of a crime is through improper testing. The testing process is often complicated and requires detail-oriented professionals to perform the procedures properly. One mistake or error may lead to inaccurate results, which can then lead to a wrongful conviction. Forensic analysts could also skew the results on purpose, as a way to sabotage the case. 

The way the scientific expert presents the information to the court can also sway the jury’s decision. Even validated methods, such as DNA analysis, can be applied inappropriately, yielding inaccurate results as well. 

Using outdated methods 

In addition to mistakes and misconduct, inaccurate results may be obtained if the wrong type of test or an outdated method is used. Constant improvements in testing procedures brings changes in the way evidence is processed. In some cases, researchers find that a scientific method once used to process evidence is no longer valid and does not provide accurate and reliable results. Some states have enacted legislation that allows those convicted on these outdated methods can have their cases reevaluated by the courts. 

Some methods that have been discredited include the following: 

  • Blood splatter patterns 
  • Hair follicle comparisons 
  • Tire tread mark analysis 
  • Bullet lead analysis 
  • Evaluation of wood patterns in arson 

It is critical to look at the methods in which the evidence was processed to ensure the results are truly accurate.