Free Paper Sample on Forensic Evidence

Published: 2023-01-22
Free Paper Sample on Forensic Evidence
Type of paper:  Research paper
Categories:  Forensic science
Pages: 6
Wordcount: 1379 words
12 min read


Recognition and determination of body fluids at the scenes of crime may give very vital data as to the happenings which could have taken place and the individuals involved. The existence of fluids of the body like semen, saliva and even blood and the DNA profile has gotten from them may provide police agency with essential information to help the inspection. After the collecting the required evidence, it should be taken to the lab where it is tested in an attempt to determine the individuals who were involved in the crime. In this paper, I will define how proper handling and transportation of forensic evidence should be as well as how to test three body fluids: blood, saliva and semen to collect evidence and help in investigation of a crime.

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Research questions

  • How to deliver the evidence to the lab for testing
  • How to test the three body fluids: blood, saliva and semen
  • How the tests for the three fluids are similar as well as well as how they are different.


Delivering the evidence to the lab for testing will include the proper handling and transportation using containers and without contaminating the evidence. Presumptive and confirmative tests will be used in testing the three body fluids.

Delivering the evidence for testing

Delivering the evidence to the lab for testing need a lot of care in terms of how it will be collected and transported. Most of this proof can be collected in paper packages such as bags, envelopes, and packets. The liquid evidence can be carried in non-breakable containers, which are also leak-proof. Wet or moist evidence such as body fluids from the scene of the crime should be collected, stored and transported in plastic containers to a piece of evidence receiving site if the period of storage is two hours or less to ensure that the evidence is not contaminated. Once the wet or moist evidence is in a safe place, whether packed in a paper or plastic, it ought to be taken out and allowed to entirely dry. The evidence can then be packed in a new dry paper or container then transported to the lab. Any evidence containing moisture should not take more than two hours in a paper or plastic carriers for moisture leads to the development of microorganisms, which might damage or alter the evidence. Any of the evidence that can contaminate another must be packed separately. The containers into which the evidence is transported in should be closed and secured to block the contact of evidence when being carried. Each container must have: the date and eve time the proof was gathered, the details of the

Individual who gathered it, name of the inspecting agency as well as their file number, and also a full description of the evidence as well as where it was collected. Every kind of evidence has a particular value in an investigation which should be kept on the top of the mind by the investigator when doing an investigation in a crime scene.

Testing of body fluids


Blood is undoubtedly the most usual fluid of the body of interest found in the scenes of crime, which is comprised of water, glucose, minerals, proteins, hormones as well as many metabolites. Because of the usual importance of blood in the context of forensic, numerous tests for determining blood have been enhanced. In the past years, plausible tests might be used at the scene of the crime to identify if the suspected stain is real blood. Firstly, to clarify that the alleged evidence is blood, I will use Luminol, which is a well-known presumptive test. Luminol results in an individual blue luminescence in the incidence of blood, hinged on the oxidation of Luminol by hemoglobin. Likewise, fluorescein is hinged on the heme-accelerated fluorescein oxidization to fluorescein, although a secondary source of light is required to visualize the change. I will also use phenolphthalein, which is another presumptive test for blood, which makes an alkaline solution to turn pink in color in the existence of blood. After determining and confirming whether this is blood, I will then conduct a DNA test to identify the owner of the fluids.


Saliva may be flexible in terms of composition, precisely because of the consumption of food or the time the saliva is produced. Saliva is composed of nearly entirely water, together with electrolytes, enzymes, mucus, epithelial proteins, cells as well as endogenous and exogenous metabolites. Testing the saliva that was encountered during the criminal investigation, I will use alternative light sources as with blood. To identify whether it is saliva, I will test the prescience of amylase, which is an enzyme found in different body fluids but found in large volume in saliva. When in interaction with saliva, the starch-iodine test turns in a blue color transformation, which is due to the presence of starch formed from the salivary amylase breakdown. Correspondingly, the test of amylose Azure results in a blue color transformation following hydrolysis in amylase.


This is a vicious body liquid that is secreted by the testes, comprising various constituents counting lipids, enzymes, sugars, and obvious spermatozoa. Semen I this forensic context is essential for it can indicate the evidence for sexual assault. While testing the semen, I will primarily target to detect acid kinase, which is a secretase formed in more enormous quantities by the prostate, if positive, it leads to an observable color change. Since this test can as well react with virginal acid phosphates leading to false positives, I will also use simple microscopy to confirm the occurrence of sperm cells, basically using a Christmas tree stain technique. This technique will allow me to visualize the heads of the sperms. In the semen test, I will also use an immunological method, which is a rapid station determination for semen test. The immune process is hinged on the uncovering of semenogelin, a natural protein found in the human semen.

After detecting and identifying that the three fluids were blood, saliva, and semen, then I will conduct a DNA test which will aid in further investigations and also to identify the owners of the body fluids, and identify the individuals who were involved in the scene.

Similarities of the three tests

During the test of these body fluids, I will use two categories of inspections: confirmatory and presumptive, to locate, determine, and confirm these body fluids. The two types of tests are differentiated by their uniqueness, and, then, the level of confidence in the determination of the body fluids. The confirmatory tests allow the precise definition of the body fluids whereby presumptive tests only offers a preliminary sign of the existence of the three body fluid. Another similarity in the test of the three body fluids is that visualizations will be used to detect and determine the body fluids.

Differences of the three tests

In each of the three body fluids, I will test different components that could help me determine whether the fluid was present or not. For example, in the blood, hemoglobin is the critical component of the blood to be tested. The oxidization of the Luminol by hemoglobin turns into a distinctive blue luminescence. In saliva, I will test the presence of amylase in the fluid. In interaction with the fluid, the starch-iodine turns to blue color transformation, which means there is the presence of amylase, and the liquid is saliva. In the semen test, I will be primarily targeting to test the presence of acid phosphate.


Through proper transportation of the evidence to the lab without contamination and effective testing of the three body fluids will provide clear information that will help in the investigation of the crime. This evidence will then be used in the court once the defendant is arrested.


Buckleton, J. S., Bright, J. A., & Taylor, D. (Eds.). (2016). Forensic DNA evidence interpretation. CRC press.

Ivanovic, A. (2018). ThE wAy OF hANdLiNg EvidENCE OF CrimiNAL OFFENCES OF COmPuTEr CrimE. Criminal Justice and Security in Central and Eastern Europe, 202.

Orphanou, C. M. (2015). The detection and discrimination of human body fluids using ATR FT-IR spectroscopy. Forensic science international, 252, e10-e16.

Robertson, B., Vignaux, G. A., & Berger, C. E. (2016). Interpreting evidence: evaluating forensic science in the courtroom. John Wiley & Sons.

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