Can you trust DNA evidence?

DNA evidence plays a vital role in criminal investigations. It has helped clear innocent people and helped convict others. Yet, it is not as reliable as you may think.

Mixed samples are one issue, especially with DNA taken from saliva or blood. If the forensic team takes a DNA sample from a door handle, it could contain bits of several people’s DNA and lead to wrong conclusions.

DNA gets everywhere and is easily transferred

Let’s say you work as a hairdresser, and the police found one of your hairs at the crime scene inside a restaurant. Here are some reasons that you could be wrongfully charged due to DNA evidence:

  • You visited the restaurant on another occasion: The police have no way of knowing when the hair got there. You could even have been there at the time of the crime but had nothing to do with it.
  • Someone carried your hair there: Perhaps your hair fell onto the clothing of a client whose hair you were cutting. When they visited the restaurant it dropped off.
  • Someone placed your hair there: If someone wanted to frame you, they could easily get one of your hairs. They could pick it off your clothing as they walk past, or collect it from a seat you sat in.
  • The police or lab mixed the sample up: Incorrect storage or labeling is always possible. This is uncommon, but it has led to innocent people being arrested in the past.

There are several reasons why investigators can draw wrong conclusions when they find DNA at a crime scene or on the victim of a crime. Understanding more about its flaws will be crucial if charged with a crime.