Introduction
Crime scenes yield DNA traces, and the recovery of these traces has decisive significance for reenacting and solving crimes, providing the criminal justice system with an impartial indication (Mapes, Kloosterman, & Poot, 2015). There are various techniques used for this purpose, and all these techniques are well-established and scientifically validated (Lubaale, 2015). Thus, DNA databases are often mentioned as competent crime-fighting contrivances, as these can also support the exoneration of unfairly imprisoned persons (Mapes et al., 2015). There are certain characteristics of DNA that make it possible to be used in forensic genetics. Individuals have DNA, which is the collection of their chromosomes that show both visible and invisible characteristics. Forensic genetics uses these characteristics on the principle that DNA is the same in all of the cells in the bulk of an individual. It is noteworthy that not all DNA is helpful in the assessment of crimes, as it has a nonfunctioning part that is different in all individuals; forensic genetics uses this part for the assessment.
Despite the competence of the source, there are also many cases in which this evidence has given rise to disputes with reference to court decisions, leading to many questions about its potential effect on the sanctioning of certain crimes (Lawless, 2013). Although DNA is a golden guide in many crimes regarding public opinion and from the perspective of judges, there are many cases in which it loses its validity, credibility, and effectiveness in judgment, and questions arise about whether deliberate or unintentional human error is responsible.
Piloting And Conducting DNA Samples
The use of DNA as evidence in crime started in 1986 when an English inventor of this technology used it in a rape-murder case (Bishops, 1995). The use of this evidence in the courts was permitted in 1988 (Bishops, 1995). The use of these techniques is rapidly increasing, and it is evident from the fact that around 130,000 to 150,000 DNA identifications are conducted every year in America (Bishops, 1995). In some circumstances, a short tandem repeat (STR) profile of a particular person matches that of a sample taken at the crime scene and does not openly answer questions of the guilt or innocence of that individual (Lubaale, 2015). The successful use of DNA in crimes depends on certain aspects, including the sample size and the purity of the sample taken for the investigation (Lubaale, 2015). The validity of the DNA sample varies over time and depends upon the sample collected. If the DNA is collected promptly and properly saved, its life increases and it can be used for a longer period (Lubaale, 2015).
The sources of DNA collection from the body of the person are the blood of the person, the sperm and semen cells, tissues as well as the organs, the bones of the person and his teeth, and any other body secretion or the epithelial cells present on the body of the person or his clothes (Lubaale, 2015). The technique widely used by scientists for DNA profiling intended for use in investigations is STR, and it uses the polymerase chain reaction for its functioning (Lubaale, 2015). PCR, with the ability to produce millions of copies, is then used in the DNA analysis of criminals (Lubaale, 2015). The copies that PCR produces are then subjected to electrophoresis, producing an electropherogram that is a computer-generated graph (Lubaale, 2015).
DNA traces from the crime scene are transferred to the police forensic department and referred to the forensic laboratory after consent is taken from the public prosecutor (Mapes, Kloosterman, & Poot, 2015). When they reach the lab, they are profiled under strict protocol (Mapes et al., 2015). There are two types of criminal cases, and the processing of the DNA varies and depends on the type of case under exploration (Mapes et al., 2015). These are the SC cases and HCV cases (Mapes et al., 2015). Their handling not only requires different specialized SC officers, but they are also processed differently concerning their arrival at the labs (Mapes et al., 2015).
The Technique Of Analyzing And Interpreting DNA
UK Forensic Science Service (FSS) used the first technique, the LT-DNA technique, for processing the DNA samples used for the investigation of crime (Lawless, 2013). There were many incremental adoptions of this technique by scientists for its effective use. It used the probabilistic Bayesian system as its operating mechanism, and this method was successfully used before the collapse of a high-profile case in 2007, due to which doubts arose about its reliability.
“My study reveals how the technological boundaries that surround LT-DNA showed a high level of multivalency. In the debate discussed here, a series of distinctions were drawn: basic distinctions between ‘valid’ science versus potential ‘pathological science and ‘new’ versus ‘the same technology, as well as some more subtle distinctions (LT-DNA as a ‘tool’ vs. LT-DNA as a set of ‘conditions’)”. (Lawless, 2013).
In the above, the researcher is highlighting the role of technology in DNA enhancement. However, like technology, innovations and changes in technology are subject to changes in science as well. The study introduced the argument about accuracy in the field of DNA by exploring “Pathological science.”
There is controversy associated with the use of the DNA technique about its interpretation as well. There are many critical problems that arise during the interpretation of the results that make the use of these techniques unreliable in many circumstances. One such example of the controversial interpretation of the results of DNA analysis is the Bokolo case. The petitioner, in this case, was accused of the rape, murder, and battering of the child (Lubaale, 2015). The evidence in the court only found him guilty of the charge of rape, and he appealed to the Supreme Court against this decision. All the decisions of the court rested upon the evidence from the DNA, and the petitioner denied his presence at the site of the crime (Lubaale, 2015).
The STR profile of the accused was not in dispute when investigated for the results. There were two interpreters interpreting these results; one was from the defense, and the other was from the prosecution. Both interpreted the results differently, pointing out the weaknesses and shortcomings of the techniques that arose in that particular case (Lawless, 2013). The opinion of the prosecutor was more convincing in this case, and the court had to consider it. When it was analyzed from the other point of view, it seemed that the opinion of the defense was more convincing. The results do not interpret themselves, but the experts interpret them and introduce subjectivity into their opinions, making the results biased; this is one of the solid objections raised by scientists and forensic experts while dealing with DNA profiling as a test of evidence in criminal cases. Thus, the Bokolo case took into account the alternative interpretation and showed the weakness of this technique effectively.
There is some useful guidance given by Thompson et al. that provides suitable assistance to defense experts so that they can use DNA evidence effectively in courts and interpret it efficiently (Lubaale, 2015). There is a need to give the defense expert access to the report of the DNA analysis (Lubaale, 2015). The report should have a detailed description of the tested samples, the type of DNA testing being performed on that DNA sample, as well as an indication of the common source that the sample had for the testing (Lubaale, 2015). This guidance is suggested to the defense expert so that he may thoroughly analyze the report and interpret it effectively in court as evidence in criminal cases.
The O.J. Simpson Case
Los Angeles police detectives sought to determine whether a knife reportedly found on O.J. Simpson’s former property in the late 1990s contained the DNA of the football star or the two murder victims. While the LAPD spent considerable effort conducting forensic examination of the knife, police sources said DNA testing was likely to be a key issue for researchers (Winton, 2016).
Sources said a preliminary examination suggested the weapon was not connected to the brutal 1994 murders of Simpson’s ex-wife, Nicole Brown Simpson, and her friend Ronald Goldman. It was unclear whether any DNA was on the knife and how long it had been since it was discovered on the Simpson property.
Simpson was tried for murder, but the jury found him innocent.
Presumably, the knife was found when crews were working on Simpson’s Brentwood property after it was sold. But the owner of the company that did the demolition said that no one had found a knife.
“I think it’s a joke. I think it’s just filler … no one on my crew found anything,” said Mike Weber, 70. “I had instructed my people, ‘If you find anything, don’t keep it. Tell me, we’ll take the appropriate action.’”
A Los Angeles police officer turned over the knife to the LAPD after keeping it for many years, his lawyer said Friday (Winton, 2016).
Preservation Of DNA Evidence
There is a need to preserve DNA evidence properly so that it can be used in courts for interpretation as a source of evidence in crimes. There are various techniques that provide results from preserved DNA. As Lubaale (2014) claims, “Although cross-examination is supposedly the ‘greatest engine ever invented for the discovery of truth’, arguably, the complexity of the technique of DNA pro ling limits the effectiveness of cross-examination”.
It is important to understand the techniques for preservation of DNA. According to the above study, time is a factor that can cause the elements to make results inaccurate. Hence, the preservation of DNA could prove ineffective at times as well.
Conclusion
There is a long history of debate over DNA evidence, known as the DNA wars, during the period between the 1980s and the early 1990s (Lawless, 2013). There are many legal and scientific challenges to these forensic techniques that have put the use of this technique in question; this controversy gained importance with the participation of genetic scientists by providing evidence against this technique (Lawless, 2013). Incorrect usage of DNA evidence can lead to a miscarriage of justice in which the innocent are convicted and the guilty are acquitted.
All these concerns can be addressed and this technique can be made effective if it becomes possible to conduct DNA analysis in real-time at crime scenes (Mapes et al., 2015). Efforts have begun for the further improvement of DNA analysis and interpretation techniques to remove all the objections and weaknesses of this technique (Mapes et al., 2015). Efforts are continuing, and there have been recent advancements in forensic DNA technology in the form of phenotypic profiling and familial searching (Lawless, 2013).
We don’t deny the valuable role of DNA in proving innocence or guilt and in achieving justice in many criminal cases. However, this evidence should be evaluated, and methods of collecting, analyzing, and preserving it should be evaluated in ways that eliminate the possibility of invalidation and promote the development of the technology used in testing it. Furthermore, personal and confidential rights should be kept in mind.
References
Bishops, J. E. (1995). report information from ProQuest. The Globe and Mail, Toronto, Ont.
Lawless, C. J. (2013). The low template DNA profiling controversy: Biolegality and boundary work among forensic scientists. Social Studies of Science, 43(2), 191–214.
Lubaale, E. C. (2015). Bokolo v S 2014 (1) sacr 66 (SCA): The practicality of challenging DNA evidence in court. SA Crime Quarterly, (52), 39–47.
Mapes, A. A., Kloosterman, A. D., & Poot, C. J. (2015). DNA in the criminal justice system: the DNA success story in perspective. Journal of Forensic Sciences, 60(4), 851–856.
Winton Richard, (2016, March). Knife in O.J. Simpson case: DNA test should show if it’s evidence or another false start. Retrieved from https://www.latimes.com/local/lanow/la-me-ln-oj-simpson-case-knife-dna-test-20160307-story.html
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