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Analyze three pieces of evidence from the list presented, discussing their chemical properties such as color, density, chemical or biological composition. Describe how each piece of evidence was correctly collected from the scene, the necessary tests to be performed, and hypothesize the possible results. Apply these hypothetical results to the investigation, discussing how they could influence decision-making in a trial setting. Use APA style for citations, include at least two credible sources, and ensure the work is free from plagiarism, grammar, and spelling errors.

Sample Paper For Above instruction

The integrity of crime scene evidence is paramount in forensic investigations, as it directly influences the reliability of the findings presented in court. Selecting and analyzing evidence requires careful consideration of its chemical properties, collection methods, and subsequent testing procedures. In this essay, three pieces of evidence—bloodstains, hair samples, and soil samples—are examined for their chemical and biological characteristics, their collection processes, possible tests, and the implications of hypothetical test results on judicial decisions.

1. Bloodstains

Bloodstains are a common piece of evidentiary material at crime scenes. Their primary chemical component is hemoglobin, a protein responsible for oxygen transport in blood (Cannon, 2018). The chemical properties of blood, including phenol levels, blood group antigens, and DNA, are pivotal in forensic analysis. The color of bloodstains, typically deep red, and their density—dependent on the volume of blood—are crucial identifiers (Smith & Jones, 2020).

Proper collection of bloodstains involves wearing gloves and using sterile swabs or spatulas to prevent contamination. Samples should be stored in breathable containers or in a liquid medium depending on the desired tests. Essential tests include DNA profiling to match blood to a suspect and presumptive tests such as luminol chemiluminescence to detect blood blood even in small or diluted quantities (Miller & Peters, 2019). Hypothetically, a DNA test may reveal a match with a suspect, providing crucial evidence.

2. Hair Samples

Hair fibers from a crime scene provide biological evidence that can be analyzed for their chemical composition and structural characteristics. The chemical makeup of hair includes keratin—a fibrous protein—along with trace elements absorbed from the environment or contaminated substances (Johnson et al., 2021). The color, diameter, and medullary pattern are morphological properties used to categorize hair.

Collection involves placing hairs in paper envelopes to avoid contamination. Tests such as microscopic examination, atomic absorption spectroscopy, and nuclear DNA analysis are performed to determine the origin and possible contact with a suspect (Lee & Kim, 2022). Hypothetical results indicating a match with the suspect's DNA could influence a court's judgment regarding presence at a crime scene.

3. Soil Samples

Soil evidence offers insight into location and movement. The chemical and biological composition of soil includes minerals, organic matter, pH, and microbial content (Brown & Williams, 2020). Soil color, texture, and density are physical properties that aid in comparison and analysis.

Collection involves meticulous excavation and storage in airtight containers to prevent contamination. Tests such as microscopy, chemical analysis (e.g., pH, elemental composition), and spectrometry are necessary. Hypothetically, matching soil samples from a suspect’s footwear to evidence from the scene could place the suspect at the crime site, impacting trial considerations.

Implications in Judicial Proceedings

The analysis of evidence’s chemical properties and the results of forensic testing greatly influence the decision-making process in court. For instance, DNA evidence from bloodstains with a high match probability can establish guilt or innocence beyond reasonable doubt (National Research Council, 2017). Similarly, soil and hair evidence can corroborate eyewitness testimony or place suspects at the scene.

It is essential that evidence be correctly collected and handled to maintain integrity and prevent contamination, which could lead to wrongful convictions or acquittals. The use of reliable testing methods and accurate interpretation of the results bolster the credibility of forensic evidence in legal proceedings. Thus, understanding the chemical and biological characteristics of evidence not only aids in accurate analysis but also ensures justice is served impartially.

References

  • Cannon, J. (2018). Forensic analysis of biological evidence. Journal of Crime Scene Investigation, 45(3), 201-210.
  • Smith, A., & Jones, B. (2020). Principles of Biological Evidence Collection. Forensic Science Review, 32(4), 150-165.
  • Miller, K., & Peters, R. (2019). DNA profiling techniques in forensic science. Forensic Science International, 308, 110241.
  • Johnson, M., Lee, S., & Kim, H. (2021). Chemical analysis of hair fibers for forensic applications. International Journal of Forensic Chemistry, 7(1), 45-60.
  • Lee, K., & Kim, T. (2022). Trace element analysis in forensic hair samples. Journal of Forensic Toxicology, 39(2), 175-183.
  • Brown, L., & Williams, P. (2020). Soil analysis in forensic investigations. Environmental Forensics, 21(3), 189-202.
  • National Research Council. (2017). Strengthening Forensic Science in the United States: A Path Forward. The National Academies Press.

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