The reliability of DNA testing: a conviction based on (movable) DNA?
The development of forensic DNA testing marked a breakthrough in police and judicial investigative work. After all, everyone leaves a lot of DNA behind, unintentionally. Nowadays, the idea is that the presence of DNA also immediately implies guilt of a crime, but is that really the case?
In short, the answer to the above question is no. In fact, the presence of DNA as evidence is not evidence of presence itself. There are several reasons for this.
The cross-pollination of DNA
For example, every human leaves DNA behind with the slightest movement. This can include dander, hair, blood, sweat, saliva or semen. This means that the DNA of someone who has been at a crime scene before can be found there.
In addition, DNA can also be transferred. In a single handshake, DNA is exchanged between the people involved. Suppose person A gives person B a handshake, and then to person C, it is perfectly possible that person B's DNA will be found on person C, even though both have never met.
Because DNA is so easily transmitted, one must also be aware of contamination. Forensics must be meticulous so that any possible "cross-contamination" of DNA can be ruled out.
DNA on movable objects
Another defining element is where the DNA was found. Relevant to consider is whether the DNA is found on a movable object. Not only can on such an object DNA via applied, also a single item with your DNA on it may be found at the crime scene. An example: a bottle of soda with your DNA is found near a drug lab. Such a bottle has nothing to do with the operation of a drug lab itself. It concerns an ordinary utensil. It shows all the better that the presence of your DNA near a crime scene does not mean that you are actually involved in this crime.
DNA in the legal sense
Practice shows that judges are increasingly following the theory of movable DNA. The mere presence of DNA on a movable object is considered insufficient to prove with certainty one's involvement in certain acts as a perpetrator. The acquittal in this case therefore - rightly - forces itself upon us.
Nevertheless, DNA remains a complex matter. As soon as DNA testing is mentioned in the context of criminal proceedings, caution is required. A correct interpretation of the investigation results is imperative. In addition, appropriate legal consequences must be offered to non-exclusive DNA testing.
Do you have questions about DNA testing? With our experience in criminal cases, we can assist you with the expertise you need. Contact us at info@bannister.be or by calling 03/369 28 00.
