A successful investigation of a crime or crime scene depends upon the collection and analysis of different types of evidence. Forensic evidence is divided into two broad categories: physical evidence and biological evidence. Physical evidence take the form of non-living or inorganic items and include fingerprints, firearms, bullets, shell casings, documents, and other physical objects. Biological evidence takes the form of organic things and includes blood, saliva, urine, semen, hair, and botanic materials. Forensic evidence can be collected at a crime scene using various methods. It is important to preserve the forensic evidence that is collected to ensure no information is lost. This paper will delve into discussing the types of physical evidence that forensics investigators may encounter at a crime scene. The paper will then describe the collection and preservation of forensic evidence. This includes methods used to package forensic evidence.
After arriving at the crime, the forensics investigators observed three physical evidences: shell casings, bloody fingerprints, and drug paraphernalia. Other physical evidences that were collected include bullets, blood, muddy and bloody footprints, and tire tracks. Shell casings are significant physical evidence. First, the casings may have possible DNA evidence, markings, and fingerprints. The markings can be used to match the casings to the ammunitions or firearms used. This is achieved by entering the shell casing into the National Integrated Ballistic Information Network (NIBIN) (Dyer & Walton, 2017). NIBIN is a forensic tool used to identify, target, and prosecute shooters. In addition, NIBIN help determine the sources of crime guns (Dyer & Walton, 2017). Thus, the tool can be used to determine the shooter in the crime scene. The DNA and fingerprints on the casings can be used to tie a specific person to the crime. Every person has a unique DNA and fingerprint.
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The second physical evidence identified is bloody fingerprints. This evidence is significant because it can be used to tie a specific person to a crime. Since every person has a unique fingerprint, the bloody fingerprint from the crime scene can be entered in a database to identify the suspect (“National Forensic Science Technology Center” (US), 2013). However, the fingerprint should be collected and preserved properly. The third physical evidence collected is drug paraphernalia. Drug paraphernalia may contain DNA and fingerprints and thus should be properly collected and preserved.
Additional physical evidences that the forensics investigators may have encountered at the crime scene include bullets, blood, muddy and bloody footprints, and tire tracks. Just like shell casings, forensics investigators can match bullets to the ammunitions or firearms used using the NIBIN. Blood and bloody footprints can be used to tie a specific person to a crime by matching the DNA to the suspect using a database. Tire tracks can be used to identify the perpetrator by matching the tires with the tires of the suspected vehicle using forensics databases. This will help narrow down the type of vehicle used by the suspect. More specifically, the tire tracks can be used to determine the type and brand of the suspect’s car.
Forensic evidence differs in nature, and are thus collected differently. For example, fingerprints are collected using specialized chemicals and print lifting technologies (“National Forensic Science Technology” Center (US), 2013). These technologies help match a fingerprint collected at a crime scene to a suspect. Blood is collected using slides and scalpels. They are also collected using blood collection kits. Shell casings are handled using gloves and are usually bagged once they are identified. Generally, different forensic evidences are collected differently. Whatever the methods used to collect the evidence, it is important to ensure that the evidence is not compromised.
Once all the forensic evidence at the crime is collected, the next step is to preserve the evidence. This involves keeping the collected evidence in a safe and secure place. This helps ensure no information is lost. Physical evidence materials, such as shell casings, should be bagged and documented. In addition, the materials should be given a reference ID (“National Forensic Science Technology” Center (US), 2013). This helps locate the material easily whenever it is needed. Photographs that are collected at the crime scene also ought to be well preserved. The photographs should be put and logged with other evidences. Other forensic evidence materials that should be well documented and kept in a safe and secure place are audio recordings and video recordings of the crime scene and interviews. Forensics investigators should make copies of evidence collected, if possible.
Conclusively, the collection of physical evidence is crucial in an investigation process. Crime scenes are comprised of many physical evidences. These forensic evidences are very important because they can be used to identify a perpetrator. This has become possible with the advent of technology. Different technological tools have facilitated the process of matching physical evidence collected from a crime scene, such as blood and fingerprints, to a perpetrator. Currently, there are many forensic tools and databases. With this in mind, forensic investigators should be trained on matters relating to crime scene investigations. The training will help them have a clear understanding of how to identify, collect, and preserve forensic evidence at a crime scene.
References
Dyer, K., & Walton, R. H. (2017). National Integrated Ballistic Information Network (NIBIN). In Cold Case Homicides (pp. 371-380). CRC Press.
National Forensic Science Technology Center (US),). (2013). Crime Scene Investigation: A Guide for Law Enforcement . Bureau of Justice Assistance, US Department of Justice, National Institute of Justice, NIST, NFSTC.
