The Role of DNA in Justice

Introduction

Deoxyribonucleic acid or DNA has become a useful and important element of criminal investigations. Recovery of DNA from the crime scene and its analysis can lead to the identification of perpetrator of the offence and also be used as evidence in the prosecution of the accused. DNA has also been controversial in criminal investigations, because there are cases where DNA analysis was faulty or DNA itself was mishandled or contaminated, which led to the wrongful conviction of innocent people. However, DNA testing has also been used to exonerate accused or convicted people from the crime. In this way, DNA plays an important role in the criminal justice system. This essay discusses the relevance of DNA evidence in criminal investigations and prosecutions. The larger question that this essay seeks to answer is related to the impact of DNA recovery in court convictions. This relates to both wrongful convictions as well as correct identification of the perpetrators using DNA technology. The broader area that this essay addresses is the way DNA can be used in the criminal justice system.

1st Paragraph: Importance/relevance of DNA in the Criminal Justice System/ an investigation

Deoxyribonucleic acid or DNA is hereditary matter in every human being and other organisms. The same DNA is found in almost all of a person’s body cells and are located in the nuclear DNA (NIH, 2019). DNA information is stored as code in body cells that are made up of four chemical bases, these being, adenine (A), guanine (G), cytosine (C), and thymine (T) (NIH, 2019). There are approximately 3 billion bases in human DNA; and 99 percent of those bases are the same in all people (NIH, 2019). The identifying aspect of the DNA comes from the fact that the order, or sequence, of the bases are unique to each individual and can help determine the identity of the individual with respect to the DNA information (NIH, 2019). DNA material can be recovered from the scene of crime and there are a variety of recovery sources for such DNA material. One study that analysed the recovery sources of DNA from crime scenes found that in 1500 samples of DNA material recovered from scenes of residential burglary, commercial burglary, and theft of motor vehicle in Northamptonshire, U.K. during 2006, 63 percent of the DNA samples were recovered from saliva and cigarette ends, and the remaining samples consisted of blood, cellular DNA, and chewing gum (Bond & Hammond, 2008). Saliva, which forms the principal source for DNA recovery in such cases, can be recovered from drinking vessels, bottles, cans, to name a few as well as from cigarette ends (Bond & Hammond, 2008). Blood, which is also a principal source for DNA recovery from crime scene can be encountered in the crime scene, if the offender cut himself on the scene. Cellular DNA is a general term for DNA material that cannot be attributed to any of the other sources, and is also known as ‘‘contact’’ or ‘‘touch’’ DNA (Bond & Hammond, 2008). Cellular DNA can be recovered from surfaces that the offender may have touched, although stains of the touch may not be visible at the time, and it is typically recovered by swabbing a surface (Bond & Hammond, 2008). Cellular or touch DNA is considered to be the most problematic among the sources of recovery because there are obvious areas from which the cellular DNA can be removed and obvious item to recover from which the DNA can be removed (Bond & Hammond, 2008). Touch DNA has been sampled from a variety of items, including weapons, vehicles, clothing, bullet casings, documents, and latent fingerprints (Williamson, 2012).

As useful as DNA can be in ascertaining the identity of the perpetrator of the crime, it is not necessary that the DNA recovered from the crime scene will always lead to the identification of the perpetrator. This is so because the successful recovery of trace or contact DNA is variable, and a variety of factors can be responsible for this (Raymond, et al., 2009). These factors that can impact the recovery of DNA can include the characteristics of the donor, the substrate and environment, as well as the possible delay between contact and recovery (Raymond, et al., 2009). The nature of DNA being stochastic, it is often difficult to trace DNA because the difficulty may be in separating the effect of one variable from the other variables (Raymond, et al., 2009). There are more challenges for recovery of DNA in external environment as the chances of recovering DNA from outdoor surfaces decreases significantly over time (Raymond, et al., 2009). Therefore, the challenge for investigators may be to get the DNA samples soon after the commission of the crime, which may not always be possible because the location of crime may not be known for some time. For instance, research suggests that human cells deposited on a window frame or bag will deteriorate significantly over the course of six weeks, and any chance of recovering a DNA profile from such surfaces will be substantially reduced over time (Bond & Hammond, 2008). On the contrary, if cells are deposited and stored undisturbed in a cool and dark location, it will still be possible to recover DNA profiles after six weeks, with a higher chance of reliable DNA evidence being recovered to ascertain the identity of the perpetrator (Raymond, et al., 2009). It is generally considered that there is an unpredictability associated with trace DNA analysis, due to which defence lawyers have been able to claim any number of innocent scenarios that may have led to their clients’ DNA being recovered from the scene of crime. There are indeed many factors that may affect trace DNA recovery from the scene of crime, which are discussed later in this literature review.

Coming back to touch or trace DNA, the recovery and analysis of touch DNA as mentioned above, presents more problems and challenges as compared to other sources for DNA recovery. Touch DNA is left by a person when he touches an object and is in the form of skin cells. Touch DNA is often invisible to the naked eye, and may be deposited in smaller amounts. As compared to other sources, like bloodstains or body fluids, touch DNA presents many challenges in identifying the areas where skin cells may be present and obtaining DNA profiles from these samples (Williamson, 2012). Humans shed tens of thousands of skin cells each day and such cells are transferred to surfaces through contact, therefore, perpetrator may deposit such skin cells on surfaces of items in the crime scene; however, so can other individuals transfer skin cells at the crime scene. Crime scene investigators use wet or dry swabbing or cutting methods to collect touch DNA. This is done by rubbing the surface with a wet cotton swab, followed by a dry cotton swab for collecting possible skin cells (Williamson, 2012). Surfaces of metal, glass or plastic can be subjected to such swabbing for collection of touch DNA without contaminating the DNA from the person collecting it, or nearby surfaces or objects (Williamson, 2012). However, the touch DNA may be from the suspect or from innocent parties, for which the investigator needs to consider the potential evidentiary value of such DNA. There is always a possibility of innocent transfer of skin cells and therefore, the relationship between victim and the DNA holder needs to be considered before evidentiary value of the DNA can be determined (Williamson, 2012). In certain crimes or criminal events also, touch DNA may become relevant, such as, in the case of sexual assault by a stranger, the suspect’s DNA on the victim’s clothing will be of evidentiary value (Williamson, 2012). In the event that the victim is a survivor, then touch DNA may help corroborate the victim’s statements (Williamson, 2012). Touch or trace DNA can therefore be important for ascertaining the identity of the perpetrator.

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DNA profiles are increasingly used in forensic analyses, which is done by the identification of variations, which are called known as alleles within specific regions within the human genome. These specific regions are called ‘loci’ (s.locus) (Naughton & Tan, 2011). The first system to be used in DNA profiles was Second Generation Multiplex (SGM), which measured six different Short Tandem Repeat (STR) loci to yield a DNA profile (Naughton & Tan, 2011). This method was considered to be fool proof until several cases came to light that showed the DNA matches in criminal cases to be coincidental or false. One such case was that of Raymond Easton in 1999, which saw him being arrested for a burglary 200 miles from where he lived, due to an SGM profile from DNA recovered from crime scene (Naughton & Tan, 2011). Easton suffered from Parkinson’s disease and was not able to perform many basic functions, such as, dressing or driving, but the DNA evidence being strongly against him, the prosecution pressed with their case, only to be collapsed when strong alibi evidence showed that he could not be present at the scene of the crime (Naughton & Tan, 2011). This led to more rigorous DNA testing, with a 10-point rather than a six-point test that exonerated him of the crime due to lack of matches (Naughton & Tan, 2011). While some may use this case to argue the DNA evidence cannot be reliable in all cases for the purpose of identifying the perpetrator, it may also be argued that it was DNA evidence is what led to the exoneration of Easton. Since this case, there have been many others where innocent people were exonerated and the guilty identified on the basis of DNA evidence. The case of Melanie Road may be mentioned here as the perpetrator of her rape and murder was identified through DNA after 30 years. This case exemplifies positive identification of the perpetrator using DNA evidence.

The Colin Pitchfork case is important because it was the first case in which first murder conviction was based on DNA profiling evidence. The case is also interesting because DNA evidence was used to exonerate the original suspect in the case, Richard Buckland.

The Colin Pitchfork case involved rapes and murders of two schoolgirls. Colin Pitchfork was picked up after a woman overheard a colleague bragging about giving a sample posing as Colin Pitchfork. Colin Pitchfork was arrested in September 1987, and his DNA was found to match that of the murderer. DNA profiling and matching led to the conviction of Colin Pitchfork in January 1988, and he was sentenced to life imprisonment for the murders. The Colin Pitchfork case is a classic example of how DNA profiling can be useful in ensuring that the right person is matched to the crime. Without DNA profiling, it is likely that Richard Buckland, a 17 year old boy with learning disabilities would have been convicted of the offence, as he had confessed to the murders. Based on confession alone, Richard Buckland’s conviction in the cases could be given. On the other hand, Colin Pitchfork, the actual murdered in the cases would have never been convicted were it not for DNA profiling as there was otherwise little to link him with the crime scene. Therefore, this case exemplifies the use of DNA in crime cases.

However, to go back to Naughton and Tan (2011), the point that they are making in their article is to consider the possiblity of DNA evidence not being accurate identifier of the perpetrator, as in the case of Raymond Easton, where SGM profile yielded unreliable results and only more rigorous evidence could determine the matter more accurately. What Naughton and Tan (2011) argue is not that DNA evidence is not reliable but that there is a possiblity that it may not be reliable, which makes it incumbent for the criminal justice system to evolve a degree of caution when using this kind of evidence for prosecuting or convicting people. Considering the cases where a person has been wrongly convicted on the basis of DNA evidence, which was misread or not analysed properly, it is easy to agree with Naughton and Tan (2011) that while DNA can be useful in solving cases, this kind of evidence needs to be handled and used with caution.

2nd Paragraph: Possible Risk Factors of DNA in Crime Scene Investigation

While DNA can be useful in identifying the perpetrators of offences, it is not necessary that DNA evidence recovery will always lead to successful results in courts. There are some risk factors that are to be considered in this regard as these risk factors may vitiate the evidence at the crime scene or subject the DNA recovered to faulty analysis. Some of the major risk factors related to crime scene investigation and DNA are that of contamination of the DNA, inability to locate the DNA, or confusion caused due to secondary DNA. Therefore, risk factors are not only related to the recovered DNA, but also to the DNA, which the investigators may fail to recover. The oft-quoted statement of Paul Kirk, is relevant here:

“Wherever he steps, wherever he touches, whatever he leaves, even without consciousness, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more, bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only human failure to find it, study and understand it, can diminish its value” (Kirk, 1953, p. 4).

As Kirk (1953) notes above, DNA serves as silent evidence against the offender, and this DNA may be scattered all over the crime scene, in the form of footprints, hair, fibres, blood, or semen. This DNA is the correct assessor of the identity of the perpetrator. However, the value of the DNA can be diminished due to the failure of the investigators to find it, or to study and understand it. The risks to the DNA are related to these issues, that is, the DNA may be there but not located, or it may be located but may become contaminated, or it may not have been studied and analysed accurately. Due to these reasons, the DNA’s ability to ascertain the identity of the perpetrator may be compromised.

The David Butler case exemplifies the problems associated with the secondary transfer of DNA, in that due to such secondary transfer, an innocent person may be accused and convicted of a crime. David Bulter was accused of the murder of Anne Marie Foy, who was murdered in 2005. The accusation was on the basis of his DNA sample matching some DNA found at the scene of the crime (Barnes, 2012). The DNA sample was only a partial match of poor quality, but it led to David Butler spending 8 months in jail pending murder investigation (Barnes, 2012). The DNA transfer to the scene of crime took place as a secondary transfer, which happens when a person may be a good DNA shedder and his DNA comes into casual contact with a person who may be a bad shedder and who may shed the DNA received as a secondary transfer at the scene of crime (Naughton & Tan, 2011). In this case, David Butler had a rare skin condition, leading him to shed his DNA as flakes of skin, and leaving behind larger traces of DNA than the average person would have (Barnes, 2012). As David Butler worked as a taxi driver, it is possible that his DNA on the taxi may have got transferred to another person who may have shed David’s DNA on the crime scene (Barnes, 2012). David Butler was acquitted during trial as experts were not sure about the strength of the DNA evidence in the case (Barnes, 2012).

Crime scenes are chaotic and there is a possibility of contamination of DNA at the crime scene or proper procedures not being followed by the crime scene investigators, which may lead to the contamination of the DNA. Contamination of DNA at the crime scene can also compromise the case. A good example of this can be found in the Amanda Knox case (Obasogie, 2014). Amanda Knox, an American exchange student was convicted for murder of her roommate in Italy, on the basis of DNA evidence, which was later shown to have been contaminated due to negligent handling of the DNA (Gies, 2017). The crime scene also had traces of other DNA and there was no DNA from Amanda Knox that was present at the crime scene. Eventually, Amanda Knox was acquitted of the crime from the highest court in Italy. The DNA that the investigators claimed to have found was on the kitchen knife, which was randomly selected from the drawer of the co-accused. Forensic experts objected to this evidence as it was “low copy number” and too small to be admitted in a British or American court. (Armitage & Rogers, 2016). The overwhelming DNA evidence was that of Rudy Guede, who was eventually convicted for sexually assaulting and killing Kercher. This evidence consisted of palm prints, fingerprints, and DNA on the victim and throughout her room (Armitage & Rogers, 2016). However, some DNA of Rafaele Sollecito and Amanda Knox, these being in the nature of touch DNA of Sollecito on the clasp of a bra belonging to Kercher, and Amanda’s DNA on a knife in Sollecito’s kitchen drawer (Armitage & Rogers, 2016). This was used by the prosecutors in Italy to recreate a case of sexual games between Kercher, Knox, Guede and Sollecito, and eventual murder of Kercher (Armitage & Rogers, 2016). There were two issues with the DNA handling by the investigators in this case, these being the secondary transfer of DNA and the negligent handling and possible contamination of the DNA (Fonneløp, et al., 2015). Failure to comply with the procedures was therefore, responsible for the inaccurate analysis of the DNA in the case and led to the wrong conviction of Amanda Knox.

One question that the investigators and prosecutors should ask when they recover some DNA if it is possible that DNA could have got here by some other means. This is more important when there are possible explanations for DNA recovery at the crime scene or when the recovery of the DNA does not make sense. For example, in David Butler case, there was evidence in the form of CCTV footage which did not agree with David Butler being present at the scene of crime. This should have led the prosecutors to question the presence of DNA at this site and also whether there were some possible explanations for this. For example there could have been secondary transfer, which was later found to be the case in the David Butler case. In the case of Amanda Knox as well, this question should have been posed by the prosecutor who chose to interpret Amanda’s involvement in the crime on the basis of the trace DNA found in the knife on the kitchen. The trace DNA was of such quality that experts refused to consider the evidentiary value of this DNA. Moreover, the DNA was of Low Copy Number, which was not enough to attest to the identity of the DNA holder in the case. Both the David Butler and the Amanda Knox cases show how contamination of the DNA or the possibility of secondary transfer can be responsible for misleading the investigators in criminal cases. Therefore, it is not necessary that recovery of DNA will lead to the identification of perpetrator or the conviction in the case.

3rd Paragraph: Types of DNA recovery/ methods

DNA recovery methods include Low copy number (LCN) typing, which is technique that involves analysing low quantity DNA, and Rapid DNA- mobile, which is a technique that involves rapid swapping of DNA and analysis without human intervention. LCN (Low Copy Number) DNA testing is used to associate a DNA profile with a discrete evidence type, such as, bone or hair as well as non-discrete evidence type, such as, blood stains; although LCN is easier to associate a DNA profile with a discrete evidence type (Gill, 2001). There can be adhering DNA on bone and hair, but this can be removed, and the discrete DNA can be used to isolate the evidence (Gill, 2001). There is always a possibility of contamination of DNA to the non-discrete source, for example blood stains, where transfer of cells can happen before and after a crime event. The use of LCN DNA typing has been made so as to yield evidence even from smaller amounts of DNA as a response to the problem faced with crime scene DNA investigations, where DNA samples obtained from crime scenes could be partial, degraded or mixed, or in very minute quantities so as to compromise the evidence or make it difficult to yield DNA (Naughton & Tan, 2011). LCN DNA testing can yield profiles from smaller amounts of DNA than required for traditional DNA typing. LCN DNA typing has also led to admissibility of partial and mixed DNA evidence in criminal courts, which is one of the advantages of LCN DNA (Naughton & Tan, 2011). A conventional SGM+ analysis requires 50–100 cells of DNA to yield a profile; whereas LCN requires only 15–20 cells, to yield DNA, meaning that DNA can be yielded from small amounts of biological materials, such as skin cells or sweat residue (Naughton & Tan, 2011).

Budowle, et al. (2009) define LCN as “analysis of any DNA sample where the results are below the stochastic threshold for reliable interpretation” (p.207). Budowle, et al. (2009) also note that there are certain issues to consider in depth with regard to the use of LCN DNA techniques, including training and education of investigators, evidence handling and collection procedures, reliability of current LCN methods, interpretation and uncertainty, validation requirements, and alternate methodologies for better performance. This is a correct assessment of Budowle, et al. (2009) as can be supported by the actual cases where LCN DNA technique have been proved to be inefficient in procuring evidence that can be reliably used to convict the principal accused. Thus, LCN DNA testing has not always proved to be effective in getting a conviction; however, it may be argued that this appears to speak more to the methods used for collecting and storing the DNA evidence and not the method of LCN itself. In the UK, the Omagh bombing case exemplifies such as situation. The case relates to a terror case in Northern Ireland, in which the principal evidence for the prosecution against the principal accused, Sean Hoey, was obtained through the LCN method (Krimsky & Simoncelli, 2013). In this case, the validity of the evidence was doubted by the Judge who noted in the judgment:

“It is not my function to criticise the seemingly thoughtless and slapdash approach of police and SOCO officers to the collection, storage and transmission of what must obviously have been potential exhibits in a possible future criminal trial but it is difficult to avoid some expression of surprise that in an era in which the potential for fibre, if not DNA, contamination was well known to the police such items were so widely and routinely handled with cavalier disregard for their integrity. The position so far as NIFS is concerned is even more difficult to comprehend as everyone there must have been very well aware of the risks of improper labelling, storage and examination” (Queen v Sean Hoey, [2007] NICC 49, 2007, p. 59).

The issue that Judge Muir in the case above pointed out was not related to the efficacy of the LCN method for identifying the perpetrator but the manner and method in which the DNA was handled by the investigative agencies. Due to this, the court refused to convict the principal accused in the case. Therefore, the problem may not be in the method itself but in the handling of the DNA and the possible contamination of the DNA. In this case, there was another issue related to the LCN DNA technique, which was that there was some divergence amongst the experts on the use of the LCN DNA technique (Krimsky & Simoncelli, 2013). After the judgment of the court in Queen v Sean Hoey, [2007] NICC 49, the office of Forensic Science Regulator was established so as to further study the utility and efficacy of the LCN DNA method in criminal investigation (Butler, 2012). This was headed by Professor Caddy, whose report suggested that the jury should always be informed of the nature of the original starting material as being unknown and also that there cannot be an inference drawn as to the time of transfer of the DNA (Caddy, et al., 2008, section 7.4). The Caddy report also supports the effectiveness of the LNC DNA technique (Adam, 2016). It may be noted that LCN technique itself was not questioned in Queen v Sean Hoey, [2007] NICC 49; rather, the problems in chain of custody, which made the evidence weak (Caragine, et al., 2014).

The Omagh city bombing case shows how LCN DNA techniques can be inadequate and this substantiates the findings of Budowle, et al. (2009), wherein they emphasise on the need to consider the reliability, utility, evidence handling and collection procedures, training and uncertainty issues. In fact, Budowle, et al. (2009) also use the Omagh city bombing case but go further to explore how the LCN typing techniques have evolved since that case. Budowle, et al. (2009) write that since the Omagh city bombing casde there has been an implementation of LCN typing and more stringent provisions are put in place to reduce possible contamination of DNA, which was not so in Omagh case. In spite of these provisions, Budowle, et al. (2009) write that “these more stringent collection protocols by themselves do not address the reliability of LCN typing” (p.208). It is also pertinent to note that the findings of Caddy report are themselves inconsistent with the nature of LCN typing and there is a need for in-depth evaluation by the greater scientific community (Budowle, et al., 2009). There are several areas of concern with respect to the LCN DNA typing, which are identified by Budowle, et al. (2009). The first point of concern is that there is a greater potential for error in LCN DNA typing as compared to conventional STR typing. There are also possibilities of errors of interpretation that can be caused by a number of factors, such as, allele drop-in or drop-out, or peak height imbalance (Budowle, et al., 2009). Another area of concern is that LCN profiles not being reproducible in most cases, the probative value of the results may be unreliable (Budowle, et al., 2009). There is a lack of evidence collection and handling protocols, which may present a problem in admissibility of evidence during the case (Budowle, et al., 2009). They question the robustness of the evidence collected through the RCN DNA typing on the basis of lack of reproducible results, which means that the same result may not be achieved if the sample were analysed more than once, which is the case in STR typing that gives reproducible results that can be relied on more (Budowle, et al., 2009).

Buckleton (2009) present an argument that the issue with the LCN DNA typing and its reliability in criminal cases may not necessarily be related to the method in as much as it relates to the guidelines in place in the UK. Buckleton (2009) writes that the validation of the LCN results using the UK guidelines as opposed to the Daubert standard would lead to a set of factors that could usefully be assessed during validation. These factors can inform the reporting officer and the court of the performance of the system, but as per the UK standard, there is no need to fully align the validation with the Daubert standard (Buckleton, 2009). The UK standard is less demanding than Daubert standard in context of the scientific evidence that can be presented before the court, wherein the requirement is for indicating in the court the true status of the expert’s evidence, but not the scientific reliability of the evidence being beyond question. In other words, the UK standard merely requires that the true scientific status of the evidence is accurately reported in the court (Buckleton, 2009). This presents a difficulty with the use of LCN standard in the legal setting because there is a lack of mutual understanding and communication between the judiciary and forensic scientists on the nature of LCN typing and what is can or cannot achieve in a particular case (Buckleton, 2009).

Buckleton’s (2009) arguments speak more to the guidelines with respect to the LCN typing use in legal settings and not to the efficacy of the LCN typing method itself, in which Budowle, et al. (2009) present a more thorough understanding of the method and its areas of concern and weaknesses in a legal setting. In a more recent article, Gill and Buckleton (2010) deal in more depth as to the underlying confusion with respect to LCN DNA profile interpretation, which they attribute more to the problem of distinction between LCN DNA and conventional DNA, there being no discrete ‘cut-off’ point. Gill and Buckleton (2010) argue that the tendency to distinguish LCN and traditional DNA is counter-intuitive because there is no satisfactory definition that can be applied to distinguish between LCN DNA and traditional DNA. They go so far as to say that LCN DNA as a definition that describes a technique that employs elevated cycle number or increased injection time must be given up because of the stochastic effects associated with the analysis of this kind of typing are also observed with all DNA profiling technologies (Gill & Buckleton, 2010, p. 221).

Naughton and Tan (2011) point out three specific issues with respect to the LCN DNA typing which relate to the risks associated with LCN DNA typing, including the possibility of misleading crime investigations or possible wrongful convictions. First, the number of Polymerase Chain Reaction (PCR) cycles is increased to obtain LCN DNA profiles, which increases the risk of contamination and increases the possibility of inaccurate results; and second, even an accurately yielded DNA profile may have problems of propositions and interpretations (Naughton & Tan, 2011). An unconnected innocent person who may have touched the crime scene may also yield DNA, which is known as ‘adventitious transference’ (Naughton & Tan, 2011). The third problem is that of ‘secondary transfer of DNA’, which may happen because the perpetrator is a poor DNA shedder and he had casual contact with an innocent individual who is a good DNA shedder prior to committing the crime (Naughton & Tan, 2011). Therefore, the perpetrator may leave behind DNA of the innocent individual and not his own (Naughton & Tan, 2011).

Another method for DNA recovery is Rapid DNA- mobile. Mapes, et al. (2019) write that Mobile Rapid DNA technology can be incorporated into crime scene investigations, and these technologies have the advantage of identifying a perpetrator within hours. However, they also point out that these techniques also involve a risk of losing the sample and potential evidence (Mapes, et al., 2019). Blackman, et al. (2015) use data collected for their research to demonstrate that the ParaDNA Intelligence System displays useful DNA profiles when sampling a variety of evidence items. These items may include blood, saliva, semen and touch DNA items (Blackman, et al., 2015). Their research indicates that the method can potentially benefit forensic investigations into the crime scene (Blackman, et al., 2015). The benefits of the Rapid DNA-mobile technique are that the results can be retrieved quickly, and without human intervention. This means that there is lesser risk of contamination of DNA and the analysis is simple and straightforward (Blackman, et al., 2015). The possible risks that are attached to the use of Rapid DNA- mobile technique are related to the possibility of losing samples (Mapes, et al., 2019).

A newer technique for DNA testing is that of DNA-17, which has been inducted as the standard profiling method in England and Wales (Crown Prosecution Services, 2017). A benefit of using DNA-17 testing is that it provides improved discrimination between profiles and therefore, it reduces the probability of getting a chance match between unrelated individual DNA profiles (Crown Prosecution Services, 2017). Another benefit of the technique is that it improves sensitivity of the testing and allows the production of DNA profiles from less DNA, or poor quality DNA samples (Crown Prosecution Services, 2017).

4th Paragraph: Overturning Wrongful Convictions with the use of DNA

As there have been cases where perpetrators of crimes have been identified through DNA; there are also cases where innocent people were convicted by courts, and exonerated through DNA evidence after convictions (Connors, 1996). Some of these cases are discussed in this section to link DNA to exoneration. The case of Gilbert Alejandro is an example of exoneration due to DNA evidence. Gilbert was convicted of sexual assault in a 1990 case, based on the description of clothes by the victim and the photograph in the mug book, and was sentenced to 12 years in prison (Connors, 1996). An additional piece of evidence in the case was DNA evidence picked from the victim’s clothes, which the forensic expert testified to belong to Gilbert (Connors, 1996). However, the same DNA was subjected to further tests, which showed that the DNA on the victim’s nightgown could not have belonged to Gilbert (Connors, 1996). Gilbert had served four years of his sentence when he was acquitted and released on the basis of new DNA analysis. In England itself, there are many cases of wrongful convictions or miscarriage of justice, which have been corrected later through DNA tests or analysis. However, it may be noted that in some of these cases, the reason for wrongful conviction in the first place was also DNA (Walker & McCartney, 2010). An example of such a case is found in Birmingham Six trial and conviction. In this case, the specific DNA tests that were used were Griess test, Dr Skuse’s test, TLC and ‘sniffer test’, the first being used for tracing the nitroglycerine to the accused (Gudjonsson, 2003). The Griess Test was widely disregarded as unreliable by the majority of forensic experts who testified in the case and the TLC test was held unreliable by its creator (Gudjonsson, 2003). While the Birmingham Six were convicted, their ultimate exoneration for the offence came from the uncertainties of the quality of the forensic evidence that was presented to the court at the time of the trial (Walker & McCartney, 2010). Richard Buckland’s case also shows that the use of DNA can be made to clear the name of the original convict or accused in the case, as in this case Richard Buckland, who had confessed to the rape and murder of two 15-year-old school girls, Lynda Mann and Dawn Ashworth, was exonerated by the DNA evidence, which proved that he was not the perpetrator of these crimes. This however, was a case where the DNA evidence was used in the pre-conviction stage to prove the innocence of the principal accused. There are few cases in which DNA evidence has been used to exonerate the individual after his conviction (Johnson & Williams, 2004). One case is that of Michael Shirley, who spent 16 years in prison for the murder of Linda Cook; all through he maintained that he had not committed the crime. His conviction was finally quashed in 2003, after new DNA testing and analysis of the semen found on swabs taken from the victim, led to the recovery of DNA, which did not match Shirley as well as the victim. This led the Court of Appeal (Criminal Division) to overturn his conviction as being ‘unsafe because it was based on unreliable evidence and the new DNA evidence proved that there was a third party involved in the case (R v Shirley [2003] EWCA Crim 1976). Another case in which a DNA test years after the event divulged DNA of a third person on the victim’s clothes, and led to the exoneration of the originally convicted person is that of Victor Nealon, who had already spent 17 years in prison for the offence when he was finally exonerated in 2013 (Barnes & Robins, 2018).

Another case of exoneration after conviction is that of Sean Hodgson, who was convicted for the murder of 22-year-old Teresa De Simone, who was killed in 1979 (R v Hodgson [2009] EWCA Crim 490). Hodgson spent 27 years in prison proclaiming his innocence and his conviction was overturned in March 2009 based on the mismatch between the DNA testing of the semen sample collected at the crime scene and his profile (R v Hodgson [2009] EWCA Crim 490). The body of the victim was exhumed some months after the overturning of the conviction, which led to the recovery of DNA of the original killer, who was finally convicted and Hodgson was fully exonerated of the crime(R v Hodgson [2009] EWCA Crim 490). Although there are cases where a convict is exonerated from the crime after DNA testing has been carried out, these cases are few and far in between. There are many cases, where DNA testing is not allowed or further appeals are not allowed to be made to the Criminal Cases Review Commission (CRCC), even though there are possibilities of exonerating the convicted persons through DNA testing (Walker & McCartney, 2010). Therefore, recovery of DNA and its impact on the court process remains underutilised. In this context, the criminal justice system in England and Wales had been criticised because access provisions to DNA testing for convicted individuals is still a problematic area in England and Wales and as compared to the US, which has the best record in the world for post-conviction exoneration on the basis of DNA, the English record is dismal (Johnson & Williams, 2004). There has been a lack of consideration to the possibility of using DNA evidence for exonerating convicts, and also lack of resources allocated to the possible post conviction DNA testing apparatus (Johnson & Williams, 2004).

Conclusion

DNA testing has revolutionised the criminal justice system as this science has the capability of helping solve cases, including cold cases, and identify the perpetrators of crimes, using the DNA recovered from the scene of the crime. However, the use of DNA testing technologies has also been controversial because there have been a number of cases, where DNA recovered failed to yield results in the court of law because of the mishandling of the DNA samples, or due to wrong analysis of the DNA sample. Therefore, there are also a number of cases where DNA recovered from the crime scene has actually led to the convictions of the wrong persons. Ironically, there are also cases where DNA recovered from the crime scene and subject to analysis after the conviction, has led to the exoneration of the convicted person. In England and Wales however, there have been fewer cases that have led to such results due to the CRCC’s non-referral to appeal based on the possibility of exoneration through DNA testing. Considering all these cases, it may be reiterated that DNA recovered from the crime scene plays an important role in court convictions and may also play an important role in the overturning of court convictions. The important areas to consider are using DNA with caution and subjecting DNA analysis to careful scrutiny in the courts.

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