How Faulty Forensic Science Can Lead to Wrongful Convictions

 Posted on May 16,2022 in Criminal Law

b2ap3_thumbnail_shutterstock_2018157440.jpgWhen a person is accused of a crime, the evidence against them should be properly evaluated during an investigation by law enforcement officials. When this evidence is presented during a criminal trial, jurors should be informed about the potential for errors and the possibility that investigators came to the wrong conclusions. Unfortunately, forensic evidence is often seen as infallible, and prosecutors may claim that certain types of evidence provide incontrovertible proof of a person’s guilt. In reality, many of these forms of evidence are based on “junk science,” and the misuse or misapplication of forensic evidence can lead to wrongful convictions.

Problems With Forensic Science

There are some forms of evidence that can be scientifically evaluated to indicate whether a person did or did not commit a crime. For example, DNA evidence can often be used to identify a person, and prosecutors may argue that the presence of a person’s DNA at a crime scene demonstrates that they are guilty. However, there are multiple other types of forensic evidence that have been called into question, including:

  • Bite marks - Because people often have unique dental characteristics, so-called experts often claim that they can identify a person based on the bite patterns left on a crime victim. However, multiple studies have found that the identification of a person through bite marks is highly unreliable. Even those who claim to be experts have been found to misidentify bite marks 50 percent of the time or more. Sadly, even though this form of evidence is highly unreliable, it continues to be used in many criminal cases.

  • Hair samples - Investigators often claim that microscopic examination of hair recovered from a crime scene may determine whether hair came from a certain person. However, these methods of examination are often unreliable. An FBI study used DNA analysis of hair samples collected in criminal cases, and it found that in 11 percent of cases, even though investigators had found that hair samples were indistinguishable, they actually came from different people.

  • Footprints - Investigators may examine footprints at a crime scene to determine whether they were made by specific shoes. While these examinations can identify broad characteristics of shoes, such as their size and their specific make and model, they are less reliable when identifying unique characteristics to match footprints with a specific shoe. Since no studies have been performed to determine whether these methods are accurate, the use of this type of evidence is not likely to be scientifically valid.

  • Ballistics - Because firearms have rifling in their barrels that cause bullets to spin when fired, a gun may leave unique marks on a bullet. This may allow investigators to match a bullet with a specific firearm. However, concerns have been raised about the reliability of this type of analysis, and studies have shown that errors occur in around one out of every 66 cases. 

  • Fingerprints - It is often stated that everyone has unique fingerprints that can be used to identify them. However, this has not been scientifically proven. While fingerprints can often be a reliable method of identifying a person, many criminal cases rely on partial fingerprints that are difficult to match with a person’s complete fingerprint samples. Some studies have called the reliability of fingerprint evidence into question. While an FBI study found that the bureau’s investigators made errors in one out of 306 cases, a study of fingerprint analysis by the Miami-Dade police department found error rates in one out of 18 cases. Because of the possibility of false positives when performing fingerprint analysis, juries should be informed of the potential for errors when this type of evidence is presented in a criminal trial.

Contact Our Connecticut Criminal Law Attorney for Forensic Evidence

In many criminal cases, multiple types of evidence may be used to argue that a person committed an offense. However, this evidence may be based on faulty assumptions or unreliable methods that are not scientifically valid. At Woolf Law Firm, LLC, we can help our clients understand when they may be able to challenge different types of evidence, and we will work to ensure that a defendant’s rights will be protected throughout their case. Contact our Hartford criminal defense lawyer at 860-290-8690 to schedule a free consultation and get the legal help you need.


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