Evidence Recovery and Collection

Evidence Recovery and Collection

Various procedures must be observed while assessing and after assessing a crime scene.  One of the procedures involves evidence collection and documentation. Investigators must document the state of the crime scene by taking detailed notes and photographs of the crime scene. There are various pieces of evidence found in multiple crime scenes, including firearms, explosives, and bodily fluids. For each of these pieces of evidence, the modes of the collection also vary. Accordingly, in the case whereby evidence present at the crime scene includes drying blood, a handgun and several shell casings, and several hairs, all of which are trace evidence, various collection methods will be applied.

Drying Blood Evidence Recovery, Collection, and Analysis

            During evidence collection, crime scene investigators must be in possession of personal protective equipment (PPE). This is essential in sample collections to prevent contamination of evidence. According to Fish et al. (2015), the first test taken prior to blood evidence collection is the presumptive test that enables investigators to differentiate between blood and other substances, especially those that create stains. Common presumptive tests include; leucomalachite green and o-tolidine. Accordingly, the collection method varies depending on the material on which the bloodstain is identified. For instance, blood stains can be identified on an absorbent or non-absorbent surface.

I would employ various recovery methods at the crime scene. In the case where drying blood is on the floor, I would use wet absorption. During wet absorption of drying blood, a sterile swab is moistened using distilled or saline water (Lyman, 2011). The moistened swab is then swabbed lightly for collection of blood at a crime scene. In most cases, a collection using a swab is conducted so that the blood is concentrated in a part of the swab. Additionally, a second swab can be conducted after the first for comprehensive collection. The blood samples collected would be airdried before packaging them in a sterile tube. After collection, the sample is sent to the lab for analysis.

The other method of collecting the drying bloodstain on the floor that I would use involves using the tape lifting method. This method involves placing a noncontaminated fingerprinting tape over the stain and is lifted off to obtain a fingerprint-like sample of the blood (Castro & Coyle, 2011). The collected sample is then secured on a piece of vinyl acetate and sent to the laboratory. DNA tests are conducted in the laboratory. These DNA tests include DNA profiling, which links biological evidence and an individual, either the potential suspect or the deceased. Accordingly, blood is a vital type of biological evidence that contributes to crime scene investigation through forensic analysis.

Hand Gun Evidence Recovery, Collection, and Analysis

            During criminal investigations, all evidence in the crime scene must be collected to aid in solving the investigation. Further, the collection of a handgun involves a specific criterion. The first step of firearm collection I would employ before recovery is evidence recovery, by drawing and photographing the initial position of the handgun. The handgun must be handled as though it is loaded at all times. The purpose is to ensure the safety of all individuals at the crime scene. Additionally, while moving the handgun, it would be essential for me to avoid lifting the gun by inserting an object in the barrel; this would interfere with the evidence (Lyman, 2011). The preferred way of picking up a gun that I would use involves using two fingers on the textured part of the gun, whereby potential fingerprints cannot be erased.

Additionally, the condition of the handgun cannot be interfered with by unloading it. I would document the type and state of the gun before sending it to the lab for analysis. The type of handgun must be documented, including its make, serial number, caliber, and model. The handgun should be transported to the laboratories when deemed safe; in most cases, the handgun should be unloaded and stored carefully to prevent loss of evidence while being transported to the laboratory (Lyman, 2011). I would only transport the handgun while loaded if I delivered it personally. The ammunition of the handgun should also be stored separately. This storage is either done in a plastic bag or envelope.

In the lab, various tests are conducted. One test involves the identification of fingerprints on the handgun, which may point to the suspect. Another test is firing distance determination, which is conducted to recreate the scene during the firing of the handgun (Fish et al., 2015). Identical ammunition is used during the firing distance determination.

Shell Casing Recovery, Collection, and Analysis

            According to Lyman (2011), spent shell casing near the victim’s body is significant in an investigation. The shell casing locations may indicate the handgun angle during firing and the victim’s position when the handgun was fired. I would take photographs and notes are taken to aid in the investigation and the recreation of the crime scene. I would collect and store the Shell casings in a plastic bag or envelope for transportation to the laboratory.

In the laboratory, the shell casings are entered in a NIBIN database for comparison using the comparison microscope (Fish et al., 2015). The shell casings are checked for striations; scratches on the comparison microscopes to establish a match between the shell casings and the bullets. Accordingly, the handgun ammunition, bullets, and shell casings found at the crime scene will be compared in the laboratory. Additionally, test firing can be conducted in a water tank for comparison on the operability of the handgun.

Hair Evidence Recovery, Collection, and Analysis

The presence of hair in a crime scene is essential in contributing to solving an investigation. Human beings and animals possess hair that can point a given characteristic of hair to a given species (Deedrick, 2000). Further, hair can be passed from one individual to another in various ways, including physical contact. Accordingly, hair enables the identification of various characteristics of a suspect, in the case whereby there was physical contact between a victim and a suspect. In this case, the deceased victim possesses several hairs in their hand, indicating physical contact. I would collect the hair carefully using tools such as tweezers to prevent damaging the strands. After collection, I would place the hair in a paper packet or envelop and send it to the lab for analysis.

In the laboratory, the hair will be analyzed. Hair possesses DNA information that can be analyzed to point to a suspect through DNA profiling (Lyman, 2011). In the presence of root sheaths, PCR analysis is conducted to narrow down the group of suspects by narrowing their percentage in the general population. In the absence of root sheath, microscopic analysis is conducted to compare the various strands and to narrow down on a suspect (Deedrick, 2000). In the microscopic analysis, approximately 20 strands of hair are collected from the suspect to be compared with the hair collected from the scene. Accordingly, hair is essential in an investigation because it can be identified as human and indicate which human population the suspect may belong to.

Conclusion

In conclusion, trace evidence such as bloodstains, handguns, shell casings, and hair is vital in tracing the suspect. Investigators must handle all the evidence found in a crime scene with care to prevent contamination. Contamination of evidence leads to the loss of evidence and reduces the chances of solving an investigation. Accordingly, each type of evidence has various procedures for recovery, collection, and transportation to the laboratory for analysis.

References

Castro, D., & Coyle, H. (2011). Review: Biological Evidence Collection and Forensic Blood Identification. Identacode.org. Retrieved from http://www.identacode.org/castro_review_biological_evidence_2011.pdf.

Deedrick, D. (2000). Part 1: Hair Evidence. Lkouniv.ac.in. Retrieved from https://lkouniv.ac.in/site/writereaddata/siteContent/202004131508037738gaurav_mishra_anthro_Fbi_hair_analysis.pdf.

Fish, J., Miller, L., Braswell, M., & Wallace Jr., E. (2015). Crime scene investigation (3rd ed.). Routledge.

Lyman, M., 2011. Criminal Investigation: The Art and the Science. 6th ed. Pearson Education.

Verdon, T., Mitchell, R., & van Oorschot, R. (2014). Swabs as DNA Collection Devices for Sampling Different Biological Materials from Different Substrates. Journal Of Forensic Sciences, 59(4), 1080-1089. https://doi.org/10.1111/1556-4029.12427

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You are a crime scene investigator on a homicide, and you find that you have several types of evidence that must be photographed, logged, and recovered from that scene. More specifically, there is drying blood on the floor that needs to be collected, a handgun and several shell casing near the victim, and several hairs that are still in the hand of your deceased victim. For this assignment, you are to do the following:
• Explain how you would recover dried blood, a handgun, shell casings, and hairs that are at the crime scene.
• What tools you would use to recover the evidence?
• How would you package the evidence for safekeeping and transportation?
• What types of tests could be performed on this evidence at the crime lab?
• Provide APA citation and references for your material.
The following guidelines will be used for grading:
40% Students explain how they would recover dried blood, a handgun, shell casings, and hairs that are on the crime scene.
20% Students explain what tools they would use to recover the evidence.
10% Students explain how they would package the evidence for safekeeping and transportation.
25% Students explain what types of tests could be performed on this evidence at the crime lab.
5% APA citations and references are used to support facts posed by student posts.