Forensic Biology and Biological Fluids

Forensic Biology and Biological Fluids

Several samples were collected from a scene where the crime occurred, where an individual was accused of forcing entry into a house with one female occupant. There is a strong suspicion that he attacked her. In this scene, the evidence samples collected included carpet stains, furniture, drinking glasses, broken glasses, and clothing. With this knowledge in mind, it suffices to maintain that this paper will explore how the evidence would be safely delivered and without contamination to the laboratory for testing. Also, it will provide explanations for how to test several body fluids, such as semen, blood, and saliva, on every evidence piece. It shall also describe what the positive test for all three samples would imply and explain how the three bodily fluids tests are similar and dissimilar.

In this case, the forensic team concluded the collection of samples from the crime scene where an individual is accused of house breakage. It was reported that this female victim was home alone when she heard some weird noises and investigated. The report further posits that a man was found several blocks away running from the block and was apprehended by the police officers, pending the results from the forensic investigation team. After surveying the crime scene, the team collected evidence that included carpet stains, furniture, drinking glasses, broken glasses, and clothing. In this case, every piece of evidence was collected and appropriately packaged before delivery to the laboratory for extensive testing. In the case of broken pieces of glass, every piece must be collected and packaged correctly. As such, the pieces have to be sealed safely in the paper bindle, while the fragments that have sharp edges have to be put in small-sized containers to prevent the likelihood of their cutting through the casing (“Physical Evidence Bulletin: Glass.” 2015).

On the other hand, the majority of the glass evidence needs to be put in the containers and then placed into the outer containers, after which they are then sealed and marked. The outer containers have to be labelled to indicate the type of evidence in them to warn forensic team members that the evidence has sharp protrusions. Still, should the shards of glass be found in more than one place in the crime scene, then every shard of the glass must be independently collected concerning their location. The glass evidence is crucial in the analysis of fracture and the fracture force direction.

Furthermore, when it comes to collecting the stains from the carpet, clothing, and furniture, they have to be collected, packaged, and delivered to the laboratory for the analysis of the evidence. The carpet stains or those on the furniture’s surface should be cut out.  However, the best way to do this is to collect furniture or stained carpets (Spear, 2015). In this case, when some stains could be found on the immovable objects, they should be cut out.

Still, in a context where it is difficult to collect the whole stain or that a part cannot be collected, this stain has to be swabbed using a sterile cotton swab that has just been moistened with distilled water. It is possible to collect more of the stain as much as possible. If the stain is wet, it must be first dried before it can be packaged.

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When dealing with stains on surfaces that can be cut off, the most imperative thing is that a minimum of one square inch of the stain should be collected. In the collection of stains from clothing and furniture, the evidence has to be packaged separately, which is then followed by being placed in a cardboard box or a paper bag. They should be stacked in a way that limits the shifting of these contents (“ESH Appendix 28: Evidence and Submission Recommendations by Evidence Type.” 2019).

Nonetheless, should the stains need swabbing, the swabbing must be air-dried as well as being carefully put in a paper bag or a basic envelope. According to ESH Appendix28: Evidence Packaging and Submission Recommendations by Evidence Type (2019), stains present on drinking glasses have to be swabbed using sterile cotton that is moistened with distilled water, air-dried, enveloped, packaged securely to curtail the risk of movement.

After every piece of evidence has been safely gathered and adequately packaged, the next step is to deliver it to the lab. The delivery could be in person or through mail to one of the specified locations, as clearly mentioned in the submission sheet of evidence. (DeWine, 2011). Also, every evidence piece must be correctly labeled before getting to the laboratory as “Laboratory/Evidence.” On the envelope should be the address “Evidence receiving,“ whereby attached is a submission sheet that is fully completed with a brief synopsis of the offense (DeWine, 2011).

Testing the bodily fluids found in the crime scene includes; semen, saliva and blood making use of the light beams to test them is the most feasible method, especially because they have diverse wavelengths (Advenier et al., 2018). Using the different wavelengths in blue-green, blue, violet, red, and ultraviolet could play a crucial role in detecting the fluorescent stains from the saliva, blood, and semen. Several presumptive tests could be used to determine whether blood could be found on the pieces of evidence.

In this case, therefore, according to (Virkler & Lendnev 2009), the presumptive test is the luminal test due to the fact that it lays its basis on the capability of hemoglobin and the blood’s derivatives, which will bolster luminal oxidation in the presence of a solution that is alkaline. Some of the other tests that may be used to test blood on the evidence include various chemical tests such as spectroscopic tests, crystal tests, and chromatographic tests. It is imperative to understand that a vast majority of these tests include color changes, which would make identifications concerning the presence of blood on a piece of evidence. The most common confirmatory tests include crystal and spectroscopic tests, whereby they can prove the kind of blood that is present on the pieces of evidence, with the precision of telling whether it is animal blood or that of a human.

According to (Virkler & Lednev, 2009), other tests could determine if the body fluid is semen or something else. Just like in the case of blood samples, semen may be detected through the use of a separate source of light. In this case, the presumptive tests used in semen analysis include the seminal acid phosphate, seminal polyamine detection, and the Florence test. On the other hand, confirmatory tests include the microscopic sperm cell identification and the prostate-specific antigen test.

In the detection of saliva, it is pertinent to understand that it is the compounded biological fluid that is secreted by the acinar cells of minor salivary glands and the major salivary glands. Also, it is an indicator of diverse constituents of plasma. Over the past several years, the role it plays as a forensic and diagnostic tool has been increasingly studied and evaluated. Apart from maintaining oral structure homeostasis, including tooth integrity, it has more critical functions such as proteomics, genomics, bioinformatics, and metabolomics. It is a crucial sample as it is a discriminating element in forensic biology because it acts as the salivary gland conditions indicator and drug monitoring and toxicological monitoring.

In this case, therefore, saliva may be detected with ease using a separate light source. The saliva stains would materialize bluish-white when they are seen under ultraviolet light. The presumptive test used in saliva entails an immunological, spectroscopic, and chemical test. It is also essential to understand that the confirmatory test conducted to find traces of saliva uses an alternative source of light. Every test mentioned may also be used to detect blood, saliva, or even semen on every evidence piece discovered at the scene of the crime.

Furthermore, according to Virkler & Lednev (2009), when a blood test comes out positive, it shows in blue color as it reacts with the ethanol and the acetic acid solution. Also, a peculiar color could appear after a positive result comes out for the blood test, given that it largely depends on the underuse test. A positive result for semen is the color would turn darkish purple. A confirmatory test will also be conducted to ascertain if the test turns positive. In saliva, when the test turns out to be positive, it would indicate the presence of a-amylase activity in the stains. The α-Amylase is one of the salivary constituents. The physiological role it plays is in the digestion of starch. It is present in two isoenzymatic forms, salivary and pancreatic. In this case, according to Chatterjee (2018), the RSID (Rapid Stain Identification Series) saliva flow is a lateral immunochromatographic strip designed to detect salivary α-amylase in any given field sample, which then confirms that saliva in the given sample is present.

Lastly, it is crucial to understand that a confirmation test would follow virtually every presumptive test to determine whether the stains present are blood, semen, or saliva. The tests conducted are similar for all three samples because they may each be used to test DNA. Their similarity is also present in that these tests need not be destroyed since every bodily fluid has DNA evidence and must, therefore, be protected. The reason is that DNA is crucial in identifying the suspect or the victim and possibly exonerating an individual should they be found innocent. On the other hand, the tests are also different for the three bodily fluids because their identification of the components is different, primarily because not all similar tests could be used to identify all three fluids.

References

Advenier, S.A., Paris, B. & Piaton, E. 2018. Bloodstain Evidence: from Human Blood Identification to DNA Profiling. Retrieved from http://www.jscimedcenteral.coom/Forensic/forensics-5-1049.pdf

Chatterjee, S. (2018). Saliva as a forensic tool. Journal of Dental Problems and Solutions, 5(2), 026-028.

“DeWine, M. (2011). Physical Evidence Training Manual. London, OH: Ohio Bureau of Criminal Investigation “ESH Appendix28: Evidence Packaging and Submission Recommendation by Evidence Type.”(2019). Retrieved from www.isp.state.il.us./docs/6-420.pdf “Physical Evidence Bulletin: Glass.” (2015). Retrieved from http://www.in.govlisp/labs/files/PEB-03_Glass.pdf

Spear, F.T. (2015). Sample handling considerations for Biological Evidence and DNA Extracts, Retrieved from http://www.Crime-scene-investigatior.net/sample-handling-considerations-forbiologcal-evidence-and-DNA-extracts.html

Virkler, K. & Lednev, K.I. (2009). Analysis of body fluids for forensic purposes: From laboratory testing to non-destructive rapid confirmatory identification at a crime scene. http://www.sjsu.edu/people/steven:lee/courses/c3/52/New%20non%20destructive%20confimatory%20test-1.pdf

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Forensic Biology and Biological Fluids

You are a member of a forensic team that just finished gathering samples from a crime scene for which someone is being accused of breaking into the house and possibly attacking a female. The female victim was home alone when she heard a noise and went to investigate. A man was found running from the neighborhood a few blocks away when the police arrived. They arrested him, pending the outcome of the forensic investigation. Your forensic team surveyed the crime scene area and gathered evidence to take to the lab for investigation. The evidence consisted of broken glass, stains from carpet, furniture, clothing, and drinking glasses.
Assignments
• Address the following in 4–5 pages:
How will the evidence be delivered to the lab for testing? Explain.
How would you test for the following body fluids on each of the pieces of evidence (explain in detail):
 Blood
 Semen
 Saliva
Describe what a positive test for each of the samples would indicate.
 Be very descriptive in your examination.
How are the tests for the 3 above body fluids similar? Explain.
How are the tests for the 3 above body fluids different? Explain.
• Be sure to reference all sources using APA style.