Introduction
Crime scenes offer potential evidence for forensic laboratory examination that can be used to understand what happened. The evidence can be biological, such as DNA from blood, fibers, drawings, photographs, and documentary evidence, such as receipts (Kumar, 2022). Various tests can be conducted to derive data from the assembled items. In the case scenario provided, a deceased male lies on his back.
Other than his body, other evidence includes a rifle firearm, stains, fiber, hair, drinking glass, and bottles. It is vital to handle the evidence with care and avoid any contamination. Moreover, investigators must uphold the sample standards and select relevant materials to allow for admissibility. Although the crime scene contains a lot of evidence, applying the correct and standardized test is necessary for the investigator to be allowed to present the items in a court of law.
List of Available Forensic Tests
The CS-1 is an iPhone with a black casing; both black require latent print, and digital evidence analysis is relevant for both CS-1 and CS-3 to check any last calls, messages, and alarms. The test analysis for the deceased’s body CS-2 autopsy will reveal the cause of death and trace analysis (Dutelle, 2020). The riffle may have fingerprints, necessitating several tests, including latent fingerprints, serology, DNA analysis for the stains, and trace evidence. CS-5, the bolt action rifle, will require trace analysis for the hair and white fibers, firearm analysis to verify if the fired bullet came from it, and latent analysis for palm prints.
The silver earring CS-3, the pillow on the bed, CS-6 and CS-7, and the drinking glass require a DNA test analysis because they contain body fluids, while the fitted sheet CS-8 requires trace analysis. The three pens labeled CS-9 to CS-11 and CS-12 bottles of Smirnoff Vodka will require latent print analysis. The investigators must remove the prints from the crime scene by persevering the items and adequately documenting them, as it will serve as evidence of all the people at the crime scene (Fenoff et al., 2022).
To determine the composition, a controlled dangerous substance analysis test should be ordered for the baggies of white powder CS-14 and CS-15 and the smoking pipe CS-16. The note on the TV stand and one crumpled on the dustbin CS-17 and CS-18 require questioned document analysis to verify the handwriting, while CS-19 needs a bloodstain pattern analysis test.
Justification for Laboratory Analysis of Selected Items
Latent prints taken from surfaces touched by people contain palms and fingerprints that prove a person was within the crime vicinity. For instance, the test request for CS-1 is latent print because the phone is likely to have palm prints that can identify the people at the crime scene. Notably, latent print can be left on various items, including plastic, metal, glass, and the ground (Dutelle, 2020). In the scene, items such as pens, glass, rifle, and the bottle require latent analysis because people who were present at the crime scene are likely to have held them and left their palm and fingerprint
Trace analysis focuses on the transfer of materials and is usually microscopic but contains significant data. For instance, the deceased body CS-2 contains elements such as residues from the gunshot, fibers, and hair, all of which can be analyzed to verify identity (Dutelle, 2020). The firearm analysis is essential in the case because the victim was shot from the temple through the head. The analysis will require obtaining the test bullets and cartridge cases to compare the ammunition component and barrel to verify if it is the riffle that was used to shoot the victim (Fenoff et al., 2022). If the barrel and the bullet on the victim match, then the investigator can conclude that it was the murder weapon.
Samples/Standards for Laboratory Evidence
Forensic standards are set for all investigations to ensure reliability and uniformity in evidence collection, storage, and retrieval. In addition, during the submission of evidence, there must be a reference sample for quality control (Hundl et al., 2019). Standards are the items on the list of evidence, such as hair from the deceased body, because the source is known. DNA is assumed to be the prevailing standard in forensic investigation and will be helpful for the scene (Murrie et al., 2019). A standard test of the victim’s DNA will be taken to the laboratory for testing alongside a sample of the unstained sheet to ensure the reliability of the results.
Challenges with Evidence Admissibility
There are various conditions that an item must meet to ensure admissibility in a court of law. The assumption is that every forensic technique has some error that necessitates legal standards to guide courts in considering known error rates (Murrie et al., 2019). Furthermore, the court permanently restricts any late submission because it can encourage illegalities such as planting evidence (Mansour, 2020). For instance, one of the possible challenges for admissibility in the current case is if the evidence can be provided late. The investigator may assume some items, such as the white fiber, are unimportant but later establish that they have implicating information.
The other challenge regards the relevancy of the items collected to the crime. For example, items such as crumbled paper, earrings, and pens may not be necessary for knowing how the victim was killed. The other key challenge is when the investigator provides samples that fail to mimic the casework, especially on the trace analysis of firearms. In 2006, the Federal Bureau of Investigation (FBI) Laboratory provided the standard procedures for fingerprint admissibility on firearms to enhance validity, accuracy, and reliability (Monson et al., 2022). Therefore, if the investigators fail to use appropriate tools, such as gloves, to handle the ammunition and the distorted fingerprints, they cannot be used as evidence. Moreover, if the preservation of the evidence fails to meet standards, it will be spoilt or contaminated, barring admissibility.
Strategies to Avoid Admissibility Challenges
Investigators can avoid admissibility challenges by ensuring that before they request any forensic test, they verify if it provides significant evidence relating to the scene. Forensics urges authorities to rely solely on task-relevant information (Gardner et al., 2019). The implication is that the investigator should focus on the items that offer the most substantial evidence. In addition, the investigators can provide proof that the laboratory has blind quality control for latent prints, digital media, seized drugs, and firearms (Hundl et al., 2019). The rationale is to ensure that there was no cross-contamination of samples and that the storage was done correctly. If items that can get spoilt, such as the liquid substance inside the glass and vodka bottle, should be refrigerated at the laboratory.
Conclusion
Conclusively, investigators collect items from the crime scene to help recreate the scenario and offer evidence in court. Different laboratory tests can be done depending on the samples. Trace analysis provides microscopic evidence of the hair, fiber, and fluids to identify people present during the crime. Firearm analysis is relevant in verifying if the weapons were used latent print provide palm prints that link a person to the crime. It is vital to uphold standards in collecting, storing, and presenting relevant evidence to ensure admissibility.
References
Dutelle, A. W. (2020). An introduction to crime scene investigation (4th ed.). Jones & Bartlett Learning.
Fenoff, R., Fish, J. T., Miller, L. S., Wallace, E. W., & Braswell, M. C. (2022). Crime scene investigation (4th ed.). Taylor & Francis.
Gardner, B. O., Kelley, S., Murrie, D. C., & Blaisdell, K. N. (2019). Do evidence submission forms expose latent print examiners to task-irrelevant information? Forensic Science International, 297, 236-242. Web.
Hundl, C., Neuman, M., Rairden, A., Rearden, P., & Stout, P. (2019). Implementation of a blind quality control program in a forensic laboratory. Journal of Forensic Sciences, 65(3), 815-822. Web.
Kumar S. J. (2022). Evidences in crime scene. Justice and Law Bulletin, 1(1), 74-81. Web.
Mansour F., S. (2020). The admissibility of unlawfully obtained evidence before international courts and tribunals. The Law & Practice of International Courts and Tribunals, 19(2), 147-176. Web.
Monson, K. L., Smith, E. D., & Peters, E. M. (2022). Accuracy of comparison decisions by forensic firearms examiners. Journal of Forensic Sciences, 68(1), 86-100. Web.
Murrie, D. C., Gardner, B. O., Kelley, S., & Dror, I. E. (2019). Perceptions and estimates of error rates in forensic science: A survey of forensic analysts. Forensic Science International, 302(19), 1-36. Web.