Proving Rape by Forensic Biology - Essay Example

Forensic Biology “A murder destroys the victim’s physical body; a rapist degrades the very soul of the victim”. It is a very sad expression on the attitude of unresponsiveness of the society towards the violation of the dignity of other human beings who are affected by sex crimes. It is important to remember that rapists not only violate the privacy and the personal integrity of the victims, but they also cause inevitably serious psychological harm as well as physical damages in the act. Rape does not only affect the victim physically but it usually destroys the whole personality of the victim. The UK constitution guarantees a right of equality to all people including its women but discrimination and crimes against women manifest in different ways in the in the United Kingdom. Traditional patriarch value systems, cultural and social practices have crippled the efforts of the women in different ways. Women are still being treated as commodities just like in the old times and they are regarded as 2nd class citizens. They are discriminated against in social, economic, political and cultural fronts. They are then exploited, oppressed and dominated that they only play the stereotype roles in the whole society; this is still seen in many countries around the world. Women’s trafficking is more serious and deep rooted predicament today that any other time in the history of the world. Fortunately, the UK laws have been amended in such a sense that crimes against women, like rape, are well analyzed and the offenders are punished adequately. With the advancements in the study and analysis of DNA and the advent of forensic science, it is now a bit easy to prove rape cases conclusively, better than in the past when DNA had not been discovered (Laybourne, 2003). Forensic biology allows the testing of DNA from different evidences collected from the scene of crime and matches it with that of the offender who is then brought to justice. With the advent of computers, information technology has very much assisted in DNA fingerprinting of the evidence because the DNA of nearly citizens has been stored in databases in the country’s forensic department which makes it easy to identify the offender. The purpose of this essay is to describe how a window believe to be holding a latent fingerprint, a blood pattern on a wall, a wet stain on a white garment and a clump of white cotton fibbers, all encountered during an investigation of the scene of a rape crime can be successfully analyzed by laboratory scientists and exhibited in court. The analysis of all these evidences will involve the use of DNA fingerprinting, the analysis of the fingerprints and any other evidence that will connect the suspect to the scene or match it with a possible suspect who can be identified from the DNA data base. Following the Locard’s Principle as used in Forensic Biology, that “Every criminal carries with him some traces of evidence from the scene of crime with which he can be connected to the crime.” Therefore with the four types of evidence, it may be easy to present such evidence in court and create a strong case against the accused. The latent fingerprint on the wall was not immediately visible to the naked eye as was left at the scene of crime (Cowger, 1992). The latent fingerprints will then be exposed using fingerprinting powder and other method. The identification of this latent fingerprint will be an important part of the analysis of this evidence and will assist in apprehending the criminal. The first thing done in the laboratory during the analysis of the latent fingerprints will be dusting for the latent fingerprints to ensure that no prints are missed and they are made readily visible to the naked eye (Zabell & Sandy. 2004). Special powder will then be gently brushed over the surface to hold the fingerprints and hold them to see if they will appear. After there appearance, they will be photographed and carefully carried on a clear tape and them affixed to fingerprint cards. These fingerprints will then be scanned into the computer to cross check them against those available in the criminal database in order to obtain any matches ((Cowger, 1992).). This can also be matched against the fingerprint of the suspect already in custody to see if that person can be connected to the crime. In the UK, the Integrated Automatic Identification System (IAFIS) is the database of fingerprints used by laboratory scientists to obtain more information about fingerprints encountered at the scene of crime. The database fingerprint records are collected from criminals and citizens who undergo fingerprinting as a background routine check and this database helps the country in law enforcement exercises. With the careful analysis of the latent fingerprints from the wall at the scene of crime, the suspect will then be identified as having made the fingerprint or just eliminated all together. It is important to note that the information gathered from the latent fingerprint on wall is not conclusive; the person whose fingerprint was found to be the latent finger print may not have committed the rape crime. That is why the other evidences will then be carefully analyzed to come up with conclusive evidence to exhibit before the court. The blood stain patterns on the wall will be used to give an indication of how the rape crime took place. The shape of the blood spots will be used to estimate the velocity and the angle or distance of the struggle. If the bloodstain patter on the wall will come out elongated, it will indicate the direction in which the blood flow was moving when the blood impacted the surface. Some of the variables to be used in the analysis are: Size of the spot of blood The quantity of blood The shape of the spot of blood How the blood is distributed at the scene of crime Location of the blood stains Angle of impact Texture of the target surface (Stuart, Kish & Paulette, 2005). The analysis of this bloodstain spot on the wall at the scene of crime shows that the blood dripped vertically indicating that the source of blood was stationary and the wall smooth, hard and vertically flat. The shape of the blood stain will indicate the direction of travel of the spatter. This can also be used to indicate the sped of violence and the motion that took place in the rape crime and such a case the pointed end of the blood stain is usually pointed at the end while facing the direction of travel. From the analysis of the bloodstain pattern on the wall shows that the rape crime could have been violently committed and the wounded person was attacked by the offender wielding his weapon from the side or over his head. It also shows that the person who the blood belongs to was flung across the room. The bloodstain pattern on the wall could have also have resulted from the wounded person being dragged against the wall (Bevel, T. and Gardner, 2008). The analysis of blood will also involve determining the origin of blood to determine who eh blood came from. This is done by finding out who was wounded of the two; the offender and the victim of rape. This is done by doing a DNA analysis of blood and this will involve the biological considerations of blood. Blood is made of erythrocytes, platelets and leukocytes suspended in plasma. Of the three components, only the erythrocytes lack a nucleus. Therefore, leucocytes and platelets can be analyzed for DNA fingerprinting to determine the owner of the blood and this assists in determining the offender or the victim, if the blood came from the victim. After the blood stain analysis we will be able to: Describe the mechanism that created the bloodstain pattern on the wall Determine the direction the blood droplet was traveling by calculating angles of impact The area of origin for the bloodstain so that it landed on the wall. Presence of a subject at the scene (DNA analysis) Position of the offender and the victim during the event. The sequence of events. To refute or confirm assumptions concerning the events of the crime and the order in which they occurred. The determination of the placement and the angles of impact of the area of origin will also assist in the determination of the origin of blood. A wet stain with no visible coloring on a white garment is most likely to be semen. However, this can only be conclusively remarks by doing a semen analysis test in the forensic laboratory. Semen identification test has to be done on the stain to make sure that it is what we suspect it to be or otherwise. Acid phosphatase (AP) test will be use to identify if the wet invisible stain on the white garment is semen. Acid Phosphatase is an active enzyme usually found in semen and comes from epithelial cells of the prostate gland. AP activity is known to be 500 to 1000 times elevated in human semen that in any other body fluid and its activity is highly elevated in semen stains. Therefore, it is realizable to use AP activity as an indicator for the presence of semen in the wet stain on white garment. But before the AP test is done, the invisible wet stain on the white garment has to be made visible at first. Alternative sources of light will then be used to make the stain visible by using the Woods Lamp also referred to as the black light technique (Woods, 1919) in which the presence of semen will be evidenced by the stain responding to the illumination of loner wavelength frequencies of UV light (350 nm). UV light is visible to the human eye and when the stain is illuminated (Pearson, Bobrow, Vosa & Barlow, 1971), it will absorb the energy and then display the luminescence at a longer wavelength of visible blue light making the invisible semen become visible to the naked eye. If the stain is not semen, then the visible blue light will not appear (Auvdel, 1987). After determining that the wet stain is really semen, then a confirmation test using the AP reagent test is done. This is an enzyme presumptive test that confirms the presence of semen. The phosphate from α-napthyl phosphate is cleaved by the AP and the phosphate in turn binds with Brentamine Fast Blue B and if the semen is present, a purple azo-dye will appear. After determining that the wet stain on the white garment is really semen, then we will go ahead to determine whether the stain originated from the suspects semen by carrying out a semen DNA analysis that follows the following procedure: 1. A portion of the garment containing the stain is cut off and dipped in a special solution to dissolve the organic matter. 2. The sperm-cells are then identified from the solution using a low-power light microscope (WHO, 1992). The sperms cells appear like dead tadpoles (Menkveld & Kruger, 1991). 3. DNA is then extracted from the sperm cells (Oettle, 1986). If the stain is small, Polymerase Chain Reaction will be used to amplify the DNA. 4. The DNA is then compared with that of the suspect. Saliva or blood samples of from the suspect provide the DNA for comparison. The DNA can also be compared with that obtain from the bloodstain pattern on the wall. Comparison might be done using RFLPs or Restriction Fragment Chain Polymosrphism. If the semen sample of DNA and that of the suspect as well as that from the bloodstain on the wall are cut by the restriction enzyme into the same length and number of fragments, then the semen may be the suspect’s. More analysis on the clump of white cotton fibers found at the scene of crime can assist us in coming up with a strong collection of evidence to present before the court. The analysis of the clump of white cotton fibers depends on whether the fiber is natural of man-made. It is obvious that cotton fiber is natural because it is derived from a vegetative source. Fiber analysis will be done on this clump of cotton including: Color of the fiber Lengthwise striations Uniformity in thickness of the strand The Number of microscopic fibers in each and every strand The direction in which the fiber twists. This analysis will be very valuable in the rape case at hand because it helps to determine whether the traces of cotton fibers found on the suspect and the victim match or not. It also helps to understand that the two were at the scene of crime. The possible results will be: The type of fiber should be a cotton fiber The colour of this fiber should be white like the one found at the scene of crime. The determination of whether it is the same type of fiber found on the clothing of the victim as well as the suspect. If the above point is true then the sample should match exactly with that from the suspect or victim in terms of direction of fiber twist, lengthwise striations, number of microscopic fibers and the uniformity of thickness. Other points of similarity can be determined. With the analysis of all this evidence, several comparisons will then be done to determine whether they can be connected to the victim or the suspect. If one of the latent fingerprints on the window is said to belong to the suspect when a comparison is done with that of the suspect then it is evident that the suspect was present at the scene of crime. The analysis of the bloodstain pattern on the wall might show that the blood belonged to the victim or to the suspect depending of who was hurt during the crime. The bottom line however is that, the crime took place in a violent manner and if the blood belonged to suspect, then the victim tried to defend herself against her assailant. If the blood belonged to the victim, then the crime is said to have been a violent rape. The victim was either thrust against the wall or hit with a weapon that caused the blood to spill on the wall. A DNA analysis of blood can determine that the blood belonged to both the suspect and the victim again giving more evidence that the suspect as present at the scene of crime. The fiber analysis of the clump of white cotton fiber will also assist to support the presence of the suspect at the scene of crime. This is if the cotton fiber found on them matches the one found at the scene of crime according to the analysis described above. This evidence will not be conclusive enough to convict the suspect as the one who committed the crime in question. Most conclusive evidence is that from the wet stain on a white garment. If this stain is semen, then a DNA analysis of the stain proves that the semen belongs to the suspect, and then we have a case! This is the first evidence that the suspect might have committed the rape crime and must be brought to justice and this is the evidence to be presented in court. This evidence might give us negative or positive findings as shown above. Rape is an accusation that is easily made and hard to prove. However, it will be hard for the defense to counter this evidence especially if this evidence is supported by the victim’s word as well as that of an eye witness and from the victim’s body. Since many rapes are rarely witnessed, the circumstantial evidence that will be offered in this case will be very helpful. Reference: Auvdel. M.J. “Comparison of Laser and UV Technology used in the Detection of Body Secretions” J. For. Sci., Vol.32, p.362 (1987) Bevel, T. and Gardner, R.M. Bloodstain Pattern Analysis with an Introduction to Crime scene Reconstruction, 3rd Ed. CRC Press 2008 Cowger, J.C., 1992, Friction Ridge Skin: Comparison and Identification of Fingerprints, Boca Raton, Florida: CRC Press, Laybourne, R.C., August 18, 2003, Pioneer in Forensic Ornithology Aided Aviation", Los Angeles Times: in print edition B-9, Menkveld R, Kruger TF, et al, Atlas of human morphology, Williams and Wilkins, Baltimore, 1991 Oettle EE, An improved staining technique which facilitates sequential monitoring of the acrosome state, Development, Growth and Differentiation (Suppl.), 1986, p28 Pearson, P.L., Bobrow, M., Vosa, C.G. & Barlow, P.W. "Quinacrine Fluorescence in Mammalian Chromosomes" Nature (London) Vol. 231, p. 326 (1971) Stuart, J.H., Kish, P.E. and S., T. Paulette (2005). Principles of Bloodstain Pattern Analysis (3rd, illustrated, revised Ed.). Taylor and Francis/CRC Press. ISBN 0-8493-2014-3. http://books.google.ca/books?id=aM6hNdjHRSgC. Retrieved 2009-01-30 WHO laboratory manual for the examination of human semen and sperm-cervical mucus interaction, 3rd edition, Cambridge University Press, Avon, 1992, pp.107 Woods, R.W. “Communications Secretes au Moyen de Rayons Lumineux” Journal de Physique (Theoretical and Applied) Vol. 9 p. 77 (1919) Zabell and Sandy. 2004, "Fingerprint Evidence". Journal of Law and Policy. http://wwy.brooklaw.edu/students/journals/bjlp/jlp13i_zabell.pdf.   Read More