Starting from 2000, the first season of CSI: Crime Scene Investigation debuted on TV and soon became one of the most popular “procedural” (i.e. describing the police/investigation procedures) series in the world. Similar series, including its spin-offs (CSI:Miami and CSI:NY) but also the various NCIS, Bones, and so on, have followed in its footsteps almost always repeating the same success.
They have allowed to bring the public closer to a previously little known aspect of the investigation of crimes, even if within written fiction it had already begun to carve out an important position (for instance the novels in the series of Dr Kay Scarpetta written by Patricia Cornwell, although the perspective was slightly different), namely that of the meticulous forensics work based on physical evidence and analysis, as opposed to the classic investigation made mostly of intuition.
The success of these series has, however, given rise to a phenomenon that has still negative consequences in the field of the real forensic science, or rather of its application in the legal field. This phenomenon is called “CSI Effect”.
It is due to the fact that what these series show is mostly fiction, even if there is some reality. The viewer (or the reader in the case of the novels), who isn’t an expert in the field, is often unable to distinguish fiction from reality and that generates expectations regarding the work of real forensic investigators, in relation to actual crimes, that are anything but realistic.
In the various CSI series and the like, for example, we see that all cases are solved thanks to the discovery of physical evidence that is irrefutable to link a suspect to the crime scene and then identify them as culprit.
Beside the fact that in reality the physical proofs that can be used are often very few and difficult to interpret, it is rarely highlighted that just a few of them are to be considered really relevant from a legal point of view. This category includes those that can be 100% (or almost) traced back to a single person. In other words, the only irrefutable physical evidence is a DNA match (which has an error rate practically equal to zero, unless you have to do with identical twins) and the dear old fingerprints. But even the…