Crime Scene

Forensic science begins at the scene of a crime. Once the commission of a crime occurs, police officers and, if applicable, crime scene investigators or technicians report to the scene. Their job is to document, preserve, and collect evidence for analysis. The standard operating procedures and protocols for processing a crime scene may vary between agencies and jurisdictions but include documentation, collection, transportation, and submission of evidence to the crime laboratory (CSI, 2013). Although protocols and procedures are in place, every scene is unique. As variables are encountered, investigators must use the individual situation as their guide. Important qualities investigators should possess include flexibility, improvisation, and creativity.

Visual documentation is important before crime scene processing begins. Such documentation occurs with the use of photography and vid- eography to capture a crime scene. Victims, potential evidence, and the surroundings are shown in detail, which allows for a complete review after the scene has been processed. As technology has increased with the use of digital media, so has the chance for deception. Although digital media provides stable, long-term storage of images, lawyers are beginning to question the source and authenticity of some digital image data. Changes to images are so easy to make that altered images may be returned to an analog format and used to replace the original image. So what safeguards may forensic scientists use to assure that images remain reliable forms of evidence? First, scientists should view images in the context of the case. Next, the source of the image and the chain of custody must be considered. Finally, the importance of the image to the case needs to be weighed: Is it a key piece of evidence? Would someone try to alter it? The digital media issue has increased the awareness of a need for the adaption of standards for all forensic imaging. The National Institute of Standards and Technology’s Organization of Scientific Area Committees for Forensic Science has a focus on Digital/Multimedia and is tasked with addressing factors such as laboratory accreditation, practitioner certification, and standards.

Communication is crucial for assuring that everyone knows his or her role in processing the scene. Written communication is essential to assure that laboratory personnel get a clear picture of the crime scene and evidence as it was discovered, without having been present. Notes and sketches that are thorough, complete, and descriptive are useful. Many forensic scientists agree that if something is not documented, it did not happen. This serves everyone’s interest because the process of forensic science and law occur slowly. A case may not go to court until years after the crime occurred. Not only does the initial documentation help investigators piece evidence together, but it also serves as a reminder to scientists of what happened, who was responsible for various steps of the analysis, how things were done, and what the results showed. Notes should also provide the context of evidence because this may determine how the evidence is processed, collected, and later analyzed. For example, blood that is pooled around a victim’s body clearly demonstrates that the source of the blood is the victim. This information would serve investigators to understand the situation of the crime but also to establish how the evidence should be processed. In this example, analyzing a bloodstain pattern would be more useful than sampling the blood for DNA analysis because the DNA would only confirm what the scene indicated. In all cases, it is important to collect questioned and known samples of evidence such as hairs, fibers, blood, fingerprints, paint, soil, glass, and handwriting. Samples with a known original origin are known samples, for example, fingerprints collected from the homeowners of a burglary. When the original source is unknown, the samples are considered questioned. Crime scene examination is a crucial step in the investigative process where people preserve and collect evidence that could alter the course of someone’s life. Even simple mistakes may damage an entire investigation, so it is important for those at the crime scene to take their time, to act methodically, to document all information, and to maintain the integrity of the evidence before providing the evidence to the crime laboratory.

 
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