Biological Fluid Stain Evidence: Blood, Semen, Saliva Sample Assignment

Biological evidence which is collected for solving a particular criminal case must be handled with care by the responsible authority. There are many methods of collecting this biological evidence. It should be properly maintained before being transported to the required agencies in order to carry out DNA tests. The higher authorities must be made responsible for collecting the different biological pieces of evidence which can be helping in proving the crime committed. Forensic laboratories perform certain tests so as to determine the relevant sources of stain fluids such as blood, semen, or saliva. Ribonucleic acid (RNA) testing is the latest technique used to confirm the tests of biological samples. These samples are collected from relatives or suspects of the crime. The tests performed through the use of this biological evidence further prove that the crime was committed. It helps in finding the perpetrator involved in the case. 

INTRODUCTION

The biological fluids such as blood, semen and saliva are analysed and identified based on isoenzymes and DNA tests. These biological fluids are known as biological evidence.  Since the samples of blood, semen and saliva are liquids, this evidence can easily be detected even if they are dried up after a long time. It is performed through DNA tests as it is very well-known that no two persons can have the same DNA until they are born together as twins. There is an alternative method of removing doubts which are popularly known as the Conventional serological technique. If this technique does not provide with the desired result then the DNA tests are carried out by the responsible authorities from the samples of blood, semen and saliva. DNA analysis most often gives the correct and adequate results of the different crimes. 

Moreover, semen samples are taken for sexual assault cases in which the outcomes of the DNA tests are kept in a computer database. The DNA profiles of several cases are maintained separately through the use of a database system. This is one of the advanced and latest techniques of identifying the suspects in most criminal cases. The perpetrator can be identified with the collection and testing of semen. Biological evidence such as blood is used for solving the criminal cases of murder, accidents, rape, assault, robbery, etc. Blood evidence can help acknowledge the location of crimes as well as the determination of weapons used. It eliminates all the doubts and suspects involved in the crimes. DNA profiles of the parents or children can also be used for finding the bodies of the injured persons. In other cases, saliva can also be utilised for determining the criminal who has committed the act. A differential extraction technique can be applied which separates the different DNA profiles of two different persons on the basis of virginal secretions and sperm cells from the female and male body respectively. 

METHODS OF COLLECTING BIOLOGICAL FLUID EVIDENCE 

A large number of biological evidence are submitted to the forensic science laboratories for executing the DNA tests. This evidence must be organic in nature. The methods of collecting these samples must be free from dirt and harmful substances. It can be possible that the blood, semen or saliva is transmitted to the victim through any medium. This medium could be any person, substance, etc. After the transfer of biological evidence, it remains on the surface. The liquid form of evidence is found to be absorbed whereas the solid evidence would remain adhered. The form, as well as situations, are the basis depending upon which the method of collection is selected. The samples which are available for the particular criminal case must be collected in abundance quantity so as to ensure that the results obtained from the DNA tests would be accurate (Kline, Margaret C., David L. Duewer, Janette W. Redman, John M. Butler, and David A. Boyer, 2002). The surrounding areas do contain certain unnecessary and dirty substances which must be removed while collecting the biological evidence for further DNA tests. It must be essential to follow the forensic practices in packing the samples from the crime areas. The forensic laboratory should receive the sample collected by the researchers. A cool and dry area at room temperature is preferred for storing the biological substances (Lee, H., Ed., 1995).

In the method of DNA analysis, the blood or saliva of the suspected individual is matched with that of the victim suffered on a probability basis. The PCR method of DNA analysis or conventional serological techniques can be used to find the criminal involved in the case. The sample is to be collected from the offender as well as a victim as biological evidence which is mainly in the form of liquids. About 5 ml blood is taken in each of the two tubes which are labeled with the date, name, location, etc. A syringe or disposable pipette is used to transfer the blood in those tubes. On the other hand, the dried form of samples found on weapons, etc. are collected and sealed along with labels (Lee HC, Ladd C, Bourke MT, Pagliaro E, Tirnady F., 1994).

The semen evidence can be collected through photographs, videos, sketching, etc. A clean syringe is used to transfer the evidence in the test tube which is to be submitted in the laboratory as soon as possible for executing the DNA tests. Labeling must be done on the tube with the date, location and name of the case.

ESSENTIAL STEPS TO BE TAKEN

In case of blood evidence- 

1. The analysis of blood is to be performed to confirm whether it is blood or not. The factors such as weather and age might affect the colour as well as the appearance of actual blood.
2. After the confirmation of blood evidence then the species must be identified properly. If it is the blood of any human or animal should be checked.
3. The methods of isoenzyme and DNA analysis must be applied if the blood is found to be human. The blood varies from person to person as the genes transferred from the parents differ in all aspects.
4. Then, DNA profiling is performed by the authority of the agency.
5. The size, quality and distribution of blood at the scene can provide more information which would make it easy for the researchers to reach the criminal.
6. The DNA tests provide with important information regarding the gender of the suspected person whose blood was being detected.
7. Further tests are performed in the private laboratories by the experts.
8. In every serious case, DNA tests need only two to three sample evidence for giving the desired outcomes required for accurate investigation.

In case of semen and saliva evidence-

1. The presence of prostatic acid phosphatase, spermatozoa or P-30 protein is required for determining the strains of semen in the body of suspected. The DNA typing further identifies the semen.
2. The presence of amylase is required to determine the saliva of the suspected. DNA typing is used in this case also for further identification. 

THESIS STATEMENT

Biological evidence is in the form of liquid evidence which confirms the crime committed by the offender.  In the entire population, about one person in every 5000 trillion people is found to have the same DNA as suspected in the particular case. It is beneficial to collect as many samples as possible from similar sources available (Lee, Steven B., Kimberly C. Clabaugh, Brie Silva, Kingsley O. Odigie, Michael D. Coble, Odile Loreille, Melissa Scheible, et al., 2012).  There must be no carelessness involved in the process of investigation through biological evidence. Some of the biological evidence is not visible such as saliva and semen so it becomes a difficult task at times for the researchers (Thornton, J. I., (Ed.) Kirk, P., 1974). There are several biological pieces of evidence that are to be detected through different effective methods. The samples are subject to deterioration which arises the necessity of storing them safely and properly. It has been found by the researchers that the outcomes of the DNA tests depend upon the development of the technologies. The DNA research shows that it can be applied only in some of criminal cases and not all types of investigations in terms of money and time. The presentation of DNA tests in court is not possible at times which creates a problem in solving the crimes committed by the offender. The investment made in terms of money or any value to the responsible authority for DNA evidence is generally wasted and not worth it. The improvements in the mechanism of handling biological evidence are essential for providing the best results in any investigation. The realistic experiments were not applied in the cases for obtaining effective solutions (Inman, K., Rudin N., 1997).

DEFINITION OF BIOLOGICAL EVIDENCE

Biological evidence refers to forensic science which involves fluid materials such as saliva, semen, blood, etc. This evidence is collected by forensic scientists in order to carry out the investigation process required to find the criminal. The serious cases of assault, murder, sexual crimes, robbery, etc. are handled with the help of these biological fluids. The samples are found to be represented in court as proof of the crime performed by the offender. This is the best and most appropriate method applied to investigate and identify the criminals involved in the act (Chisum, W.J., & Turvey, B, 2000).

The biological evidence can be collected through photographs. It is feasible, the entire part of the evidence can be collected physically also. The straining part must be taken away if the material is too large to be handled. This evidence must be collected after they have dried up in case they are wet. The preservation of these organic materials should be performed in frozen or cool areas. The storage at room temperature is best suitable for these fluids.

These biological evidence must be handled carefully by the higher authorities. The samples of biological fluids are not easy to be found. The safety measures must be taken in order to keep these evidence away from the harmful hazards such as-

1. The disposable gloves must be worn by the user while handling the biological fluids evidence. In some cases, a mask or other protective clothing should be worn by the detector.
2. The samples must not be mixed with each other so the gloves must be changed regularly after use. 
3. Utensils that are used to maintain evidence must be kept clean. 10% bleach must be applied while cleaning them. 
4. The safety protocols must be checked for keeping the biological evidence away from the biological hazards.
5. The tips of the cotton used must not be touched with the fingers.

LIMITATIONS OF THE BIOLOGICAL EVIDENCE

The biological evidence has the power of solving the most complicated crimes also. However, they are facing certain problems and limitations which need to be discussed. The higher authorities might get indulged in the misinterpretation of the results which would lead to incorrect decisions (Smith, S., and P. A. Morin, 2005).  There are several factors which can be responsible for the wrong results obtained by the DNA tests such as dirt and contamination in the samples collected, frauds, biased situations, etc. It is very difficult for the experts and researchers to keep the evidences in private and safe. The database system which is of utmost importance for maintaining the DNA profiles involves huge costs to be incurred. Furthermore, this database system is not supported by the Government or any other central bodies for its development and expansion. It has become essential to explain the authorities about the advantages of this system through which the innocent people are made free from jail and the criminals are getting arrested at the same time by the police officers. In addition, the methods of collecting these biological evidences are also not appropriate and easy. The large samples of evidence are difficult to be collected by the investigating officer (Sjöholm, Malin Ida Linnea, Joakim Dillner, and Joyce Carlson, 2007).

CONCLUSION

There are various techniques which can be applied to identify the biological fluids required to acknowledge the criminals involved in the case. All the items of the biological evidence must be submitted in the laboratories. If the laboratories are not found then the evidences must be preserved in the refrigerator and not the freezer. These fluids must be given to the crime agencies or responsible authorities as it can be helpful for them in finding the criminals of the case. DNA tests were proved to be the most powerful as well as an effective way of solving crimes. The biological evidence has decreased the level of crimes being committed by the offenders. The advanced and latest methods of collecting biological evidence for carrying out DNA tests are very helpful for specialists to solve serious criminal cases. It requires special attention in finding the samples which can expose the offender involved in the crime. The success and accuracy of the DNA tests depend highly on the process of collecting the samples and preserving them for investigation purposes. It is the way of storing and packaging which affects the decisions about the crimes (Sigurdson, A. J., M. Ha, M. Cosentino, T. Franklin, K. A. Haque, Y. Qi, C. Glaser, Y. Reid, and A. W. Bergen, 2006).

However, some of the DNA tests might give delayed results which arises a situation of inventing more advanced methods of identification. The process of finding the suspects through the use of DNA tests has been very old. For 15 years, this method is utilised by researchers and experts. DNA evidence does not provide with proper collection and preservation of biological evidence required for criminal investigation. This tool could not be used for punishing the offenders on the basis of justice. Any kind of force was involved or is not found through the DNA tests. The age and race of the person who was asked to give the sample cannot be known through DNA analysis. It further lacks in the facility of giving the information about the time delivery of the biological samples. The methods and procedures applied to obtain the evidence are also not identified in the DNA tests.

REFERENCES

1. Sigurdson, A. J., M. Ha, M. Cosentino, T. Franklin, K. A. Haque, Y. Qi, C. Glaser, Y. Reid, and A. W. Bergen. 2006. “Long-Term Storage and Recovery of Buccal Cell DNA from Treated Cards.” Cancer Epidemiology, Biomarkers and Prevention 15, no. 2 (February): 385 – 88. 
2. Sjöholm, Malin Ida Linnea, Joakim Dillner, and Joyce Carlson. 2007. “Assessing Quality and Functionality of DNA from Fresh and Archival Dried Blood Spots and Recommendations for Quality Control Guidelines.” Clinical Chemistry 53, no. 8 (August): 1401 – 07. doi:10.1373/clinchem.2007.087510. 
3. Smith, S., and P. A. Morin. 2005. “Optimal Storage Conditions for Highly Dilute DNA Samples: A Role for Trehalose as a Preserving Agent.” Journal of Forensic Sciences 50, no. 5 (September): 1101 – 08.
4. Lee, Steven B., Kimberly C. Clabaugh, Brie Silva, Kingsley O. Odigie, Michael D. Coble, Odile Loreille, Melissa Scheible, et al. 2012. “Assessing a Novel Room Temperature DNA Storage Medium for Forensic Biological Samples.” Forensic Science International: Genetics 6, no. 1 (January): 31 – 40. doi:10.1016/j.fsigen.2011.01.008.
5. Kline, Margaret C., David L. Duewer, Janette W. Redman, John M. Butler, and David A. Boyer. 2002. 2 Analytical Chemistry 74, no. 8 (March 15): 1863 – 69. doi:10.1021/ac015715e.
6. Chisum, W.J., & Turvey, B. “Evidence Dynamics: Locard’s Exchange Principle & Crime Reconstruction,” Journal of Behavioral Profiling, January, 2000, Vol. 1, No. 1 
7.  Inman, K., Rudin N., An Introduction to Forensic DNA Analysis, (New York: CRC Press, 1997)
8.  Lee, H., Ed., Physical Evidence, (Enfield, CT: Magnani & McCormick, Inc., 1995) 
9.  Thornton, J. I., (Ed.) Kirk, P., Crime Investigation, 2nd Ed., (New York: Wiley & Sons, 1974) 
10.  Lee HC, Ladd C, Bourke MT, Pagliaro E, Tirnady F. DNA typing in forensic science. Am J Forensic Med Pathol 1994;15:269-82. 8. Bourke MT, Scherczinger CA, Ladd C, Lee HC. NaOH Treatment to neutralize inhibitors of Taq polymerase. J Forensic Sci 1999;44:1046-50.