by Jennifer Nomura, UMN Law Student, MJLST Staff
DNA is a key piece of evidence in criminal trials. But despite what we see on Law and Order and CSI, obtaining a DNA sample from potential suspects isn't always easy. In an episode of a popular crime-solving TV show, detectives are shown following a number of potential suspects. The detectives pick up used tissues and discarded cigarettes from a long list of suspects in order to obtain DNA samples from each of them. Is that the criminal justice system of the future? A system where a thrown away coffee cup could be used to obtain a DNA sample from an individual, without them even knowing?
In the murder investigation of 10-year-old Jessica Ridgeway, DNA evidence is expected to play a key role in the trial. DNA of the suspect, 17-year-old Austin Sigg, was found on Ridgeway's backpack, and Ridgeway's DNA was found in Sigg's home.
The prosecution in the Ridgeway case is expected to use the DNA recovered from the backpack and Sigg's home to link him to the murder. The defense is expected to argue that the evidence recovered is unreliable. A mainstream news story, "DNA Will Play Pivotal Role in Ridgeway Case" discusses how DNA evidence can be unreliable by using the example that an innocent sneeze on the backpack could lead someone to be a murder suspect. That is an extreme example, but maybe it raises a valid point.
David H. Kaye, in The Science of DNA Identification: From the Laboratory to the Courtroom (and Beyond), raised concern over the obtainment and future use of DNA in the criminal justice system. Kaye discussed that while DNA can lead to a guilty suspect being put in jail, we should be cautious about how detectives obtain DNA from suspects and what they do with the DNA afterwards. Kaye raises questions such as: how did the police obtain a DNA sample from the suspect, was DNA obtained from other suspects during the investigation (ones who were ultimately decided to be innocent), and will the DNA sample from those other suspects be put into a criminal database to potentially be used in future investigations? These are questions that we should keep in mind as our criminal justice systems evolves.