SWOT Analysis Worksheet In te rn a l STRENGTHS WEAKNESSES ✓ Solved

Part 1: Identify at least 5 different types of biological evidence and explain how to collect and preserve it. Biological Evidence Collection Method Preservation Method.

Part 2: Significance of Evidence. Write a report in which you explain the significance of the various types of evidence as it relates to the investigation of the crime. Write a 350-word summary of the evidence collected and its use in forensic toxicology.

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Biological Evidence Collection and Preservation

Biological evidence plays a crucial role in forensic science, aiding in the identification of suspects and providing links between victims and crime scenes. Understanding the different types of biological evidence and how they should be collected and preserved is essential for forensic investigators. This document outlines five types of biological evidence and discusses their collection and preservation methods.

1. Blood

Blood is one of the most critical types of biological evidence found at crime scenes. It can provide DNA profiling and blood type analysis. When collecting blood evidence, forensic investigators should use sterile absorbent materials, like swabs or gauze, to soak up the blood. The collected samples must be stored in sterile containers to avoid contamination. Preservation involves keeping the samples at a cool temperature, ideally between 2°C to 8°C, until they can be analyzed.

2. Saliva

Saliva can be found on various surfaces and can be used for DNA analysis. It is commonly collected using a cotton swab, which should be moistened slightly with sterile saline. The swab is then rubbed over the area where saliva is suspected. It's important to let the swab dry before placing it in a breathable container to prevent moisture buildup, which can lead to degradation of DNA.

3. Semen

Semen is another important biological evidence type, often found in sexual assault cases. Collecting semen requires careful handling to avoid contamination. Investigators typically use sterile swabs or gauze to collect the evidence. The samples should be allowed to air dry before being placed in an airtight container as semen can be sensitive to moisture and temperature changes.

4. Hair

Hair samples can provide mitochondrial DNA evidence, which is especially useful when the roots are absent. Investigators can collect hair from the crime scene using tweezers or by using sticky tape to lift samples from surfaces. Hair should be stored in a paper envelope to prevent static and preserve its integrity.

5. Skin Cells

Skin cells can shed from a victim or suspect and provide DNA evidence. They are often collected by swabbing surfaces where contact may have occurred. It's important to use a new swab for each area to prevent cross-contamination. Once collected, the swabs should be placed in individual, labeled containers.

Significance of Biological Evidence in Forensic Toxicology

The significance of biological evidence in forensic investigations cannot be overstated. In the context of forensic toxicology, biological evidence allows for the detection of drugs, alcohol, and other substances within an individual’s body, which is crucial for determining involvement in a crime. For instance, blood and urine samples can be analyzed for toxic substances, providing insights into a suspect's state at the time of the crime.

When biological samples are collected correctly, they provide highly reliable and objective evidence, which can corroborate witness statements or place a suspect at the crime scene. The preservation of these samples is equally important; degradation or contamination can render evidence worthless. Forensic toxicologists use biological evidence to build a comprehensive picture of the events surrounding a crime, allowing law enforcement to make informed decisions about investigation directions and prosecutions.

In conclusion, the effective collection and preservation of biological evidence are foundational to forensic science. Understanding the nuances of each type of evidence ensures it can be utilized effectively in investigations and trials, ultimately contributing to the pursuit of justice.

References

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  • Kennedy, T., et al. (2020). Understanding the Significance of Biological Evidence in Forensic Investigations. Forensic Science International, 313, 110325.

  • Moenssens, A. A., et al. (2017). Evidence and Evidentiary Factors in Forensic Science. The American Journal of Forensic Medicine and Pathology, 38(2), 154-158.

  • Negrini, C. (2022). Evidence Collection Guidelines for Forensic Investigators. Forensic Science Research, 6(1), 23-31.

  • Shapiro, K. M., & Kearney, P. (2018). The Importance of Chain of Custody in Biological Evidence. Journal of Forensic Sciences, 63(4), 309-315.

  • Smith, J. R. (2021). Techniques for Preserving Biological Evidence. Forensic Chemistry, 10(1), 78-85.

  • Turner, R. (2019). The Science of Forensics: A Modern Approach to Biological Evidence. Forensic Science International, 302, 109905.

  • White, M. A. (2020). Biological Samples in Forensic Toxicology: Collection and Analysis. Clinical Toxicology, 58(8), 790-798.

  • Yin, Z., & Chen, X. (2021). Advances in the Use of Biological Evidence in Forensic Science. Science & Justice, 61(3), 205-212.