When the police arrive at a crime scene the yellow tape goes up securing the scene. We’ve all seen it on the television show, CSI. In fact, according to CSI Los Angeles, Miami, Navy and everywhere on television it’s the science of the crime scene investigation which solves the crime. The rest of the actors are just the means to the end. It’s the DNA, fingerprint analysis, and countless other scientific advances that lead to the solving of the crime. But, what happens to the evidence once it’s collected?
It’s the Crime Scene Investigator’s job to collect the evidence. This evidence can be identified by the first responders, the detectives at the scene, and the CSI people themselves. Some of it is located simply by drawing a chalk mark around it and some has to be found by means of instruments. Once collected it’s placed in collection containers. These can be as simple as paper lunch sacks. For example, bullet casings are often placed into paper lunch sacks. The container is then closed and secured with evidence tape, initialed by the collector, and placed into an evidence locker for later analysis or use in court.
But, what happens if the evidence is collected and then given back to the victim? For example, if a wallet is stolen, and the culprit is found a short time later with the wallet often times the police will give the wallet back to the victim. Sometimes photographs may be taken to preserve the look of the item but the possibility of forensic analysis is lost forever to the suspect. DNA analysis is no longer a possibility once the item is returned without any attempt to preserve the item for analysis.
The police do not have a duty under the law to collect evidence. It might be said that the police should collect evidence but if they don’t it’s not a constitutional violation of the suspect’s right to due process; it just might be bad police work. The United States Supreme Court has recognized that once the evidence is collected then due process imposes a duty on the prosecution to preserve “material, exculpatory evidence”. That means if the evidence is important and relevant to innocence, the failure to preserve evidence which could show a person’s innocence make the prosecution subject to sanctions. The sanctions could even be as drastic as dismissal of the charges.
In short, CSI can be critical to the defense and the prosecution. Once the evidence is collected if it is exculpatory (possibly leading to a finding of innocence) the police and prosecution can’t just throw it away or return it to the victim without risking substantial sanction for such failure. Of course, the bigger problem for the defendant is the fact that he can no longer prove his innocence and may go to prison because of that failure to preserve collected evidence. An experienced defense attorney has to be aware of this issue and ensure that CSI is a full two step process, collection and preservation for both prosecution and defense.