The Problems with Forensic Evidence in Criminal Cases

dna swab, wrongful convictions due to forensic science

The Problems with Forensic Evidence in Criminal Cases


What is Forensic Science?

When thinking about forensics, most of us imagine scientists gathering DNA evidence from a crime scene. However, there are several disciplines in the forensic field. The AAFS (American Academy of Forensic Sciences) includes eleven different types of forensics in its organization.  These range from anthropology to pathology to toxicology. 


Can Wrongful Convictions Happen Due to Forensics? 

According to PBS, “DNA is considered the most reliable of the forensic tools.” Only 2% of cases turn out to have wrongful convictions from forensic science alone. Most cases have other factors contributing to the illegitimate conviction. 

That being said, forensic science is not absolute in its consistency. A few areas for potential errors exist. For example, forensic testimonies can be misleading. There have been cases where results were fabricated or where evidence that would have led to a guilty conviction were concealed. Innocent mistakes can happen, too. Practitioners can sometimes confuse or contaminate samples. 


Can Problems be Present in Forensic Science? 

In short: yes. Improper validation of evidence can occur. 

Bite marks are a controversial piece of forensics that are sometimes used in the courtroom. Like the analysis of fingerprints, bite marks are compared to a suspect’s sample and it’s assumed that enough unique characteristics exist to set it apart from everyone else’s. However, wrongful convictions have happened due to incorrect bite mark evidence. 

Crime scenes can also be disturbed by innocents, which can lead to forensic evidence being collected on the wrong person. This happened in the case of Amanda Knox

Evidence can also be polluted if it was collected incorrectly. Officials have collected samples without wearing caps, gloves, or protective materials, resulting in contamination. 


Certified Criminal Law Specialist 

Todd Coolidge is a criminal defense attorney practicing law in Arizona. He has over 25 years of experience and has conducted hundreds of jury trials in courtrooms throughout Arizona. He is an experienced negotiator and skilled trial attorney. If you or someone you know needs excellent representation in court, contact Todd Coolidge.


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