Bloodstain Evidence Obtained from 30 Grasmere Street - Case Study Example

Bloodstain Evidence Obtained from 30 Grasmere Street Introduction About the Writer My name is (your name) and I am an expert in the field of forensic science and interpretation of DNA evidence collected from the scene of crime. I have acquired enough knowledge in both chemistry and genetics and years of field exposure on DNA analysis has reaffirmed my skills, proficiency and expertise on the discipline. Additional information on my qualification and the reasons making me suitable for this report are in the documents attached to this report. Case Summary The case is about the attempted murder of Michael Andrew Widdowson, the victim, aged 26 on July 17th 2014. The events leading to the attempted murder left the victim in a vegetative state, and as result he may be unreliable to provide first hand witness evidence. According to the crime scene report, the victim was found by the officer at about 4 pm in a vegetative state with severe head injuries and a stab wound on his chest. The incident was reported to the police by Miss Gallagher, a partner of the victim, with whom they have a child. The report lists two suspects in this case: first, Mr. Gary Hodgson, a 36 year old single man, and who is also described in the report as club owner, and secondly, Mr. Brian Andrew, a 33 single manual worker from Leicester. The two suspects gave two contradicting statements on the actions that lead to the attempt on the life of the victim. According to the first suspect’s testimony, the second suspect and he went to the victim’s house at approximately 1.00 pm. He reported that it was the second suspect who hit the victim with an object he did not recognise, and the ordeal went on till about 2.30 pm, and at which time he left the house, he noticed the second suspect rushing to the kitchen, possibly to collect a knife. On the other hand, the second suspect had a different story to tell, according to him, he did admit to have hit the victim, on the instruction of the first suspect. However, he reaffirmed that the second suspect did repeatedly hit the victim with a blunt object on the head, and then later stabbed the victim with a knife in the bathroom. The items collected from the scene of crime included the following; pair of bloodstained Reebok trainers, pair of black socks and pair of bloodstained trousers. These items were subjected to forensic tests in the lab and the DNA results for the items will be presented within the report. The purpose of this paper is to provide an investigative report whether the DNA matches those collected from the scene of the evidence. The Issues to be Addressed and a Statement of Instructions From the items collected and statement derived from the two suspects as mentioned in the paragraphs above, there are certain issues that need to be resolved from this specific case. Issues to be addressed: Does the blood found on items recovered at the scene come from a single individual or the three of them? Does the bloodstain on the pair trousers and the pair of Reebok trainers match those from either suspects or just one of them? Does the pair of black socks recovered from the crime scene contain DNA material from one of the suspect? Personal Investigation into the Facts In developing a non biased and objective personal opinion regarding this case, it would be imperative to consult and use documents, interviews and examinations, research as well as test and experiments amongst others. Secondary Sources of Information The number of the desktop and library researched sources of information that were used in drawing up of this report is listed on the reference section of the paper. Interviews and Examinations Information from interviews that pertains these case were obtained from the information and documents that were provided, and these include; the interview statement of the first suspect, the interview statement of the second suspect, and finally the statement from PC Logan, the first officer at the scene of crime. Research Background research on the case is carried out in different sections of this paper and will be listed in the text as the case continues to gain more footholds. Test and Experiments The results of the tests and experiments conducted on the specimen delivered by CP Logan were taken to the laboratories for further DNA (deoxyribonucleic acid) profiling and the sequencing chromatograms were further subject to laid down rules on interpretations. The blood and reference samples were added to a 5% suspension of chelex 100 and boiled for 2 minutes to break open the cells and release the DNA. The chelex resin is then removed by centrifugation to collect the resin at the bottom of the centrifuge tube. The DNA, which remains in solution, is removed as part of the supernatant. The yield of DNA was determined by PCR (polymerase chain reaction, a method for generating many identical copies of a particular region of DNA) amplification of a single STR (short tandem repeat) locus (the physical location of a gene on a chromosome) in order to ensure optimal performance in subsequent manipulations. The reference and evidence samples were subjected to DNA profiling or DNA fingerprinting using a standard SGM+ (second generation multiplex) PCR-based protocol. A commercially available, widely used kit (the AmpFISTR kit) was used to analyse the DNA from each sample. This system allows the analysis and comparison of 11 STR loci (the plural of locus). The results of the SGM+ multiplex-PCR reactions were analysed on an ABI PRISM 377 DNA sequence. Personal Opinion Summary It is the considered view of this paper that both the suspects: Mr. Gary Hodgson and Mr. Brian Andrew had roles in the attempted murder of the victim. Introduction The establishment of DNA analysis as a back up evidence in criminal cases is based on the fact that DNA analysis is both accurate and reliable. DNA analysis has been important has it has over the years assisted in exonerating people who were wrongfully convicted Forensic science has adapted the use of DNA profiling to unravel cover-ups after criminal offence, and this uses a technique specifically referred to as the DNA profiling which is also known as DNA fingerprinting, and this is a very powerful tool that was developed and founded on DNA evidence and has transformed forensic investigations. It has also been given credence in courts of law. Currently, DNA fingerprinting is based on short tandem repeats (STRs) plus lineage markers, and this are the Y chromosome and mitochondrial DNA. These are covered and usages are demonstrated through case analysis instances. Principles of DNA Evidence DNA is often called the genetic blueprint as it has the instruction that show the development of organisms. Features which include hair color, eye color, height and other physical features are in people’s genes, and it is known as the coding region as they provide the instructions for proteins to develop such features, and this is just only 2% of human DNA, yet the remaining 98% is taken as non coding DNA and its functions still confound the scientific community. Nonetheless, forensic science uses the non-coding segment in criminal investigations, and in this region of DNA there are unique repeating patterns which used to differentiate an individual from another. The patters already defined in this paper are known as short term repeats, and they can be measured to obtain the correct DNA profile of a person. How and Where DNA Testing is done DNA testing must be done in the laboratory with facilities and equipment acquired for such sole duties and these always meets the requirements of the courts and law enforcement authorities. I the laboratory, the DNA samples submitted must undergo a certain set of processes 1. DNA is extracted from the cell from the samples of provided, and in the under review the blood stains submitted. 2. Then the DNA is quantifies, and this is the process that entails determination of the quantitiy of DNA that is present. 3. Amplification of the DNA, and this is the process that involves production of multiple copies of the DNA so as to characterize the DNA. 4. Separation is the next step, and it entails separation of DNA product to allow for identification as the next sub step under this phase. 5. Then analysis and interpretation is the next phase, and it involves quantifying and qualifying a comparison of the DNA evidence samples taken from the crime scene to the DNA profiles. DNA Fingerprinting It is the opinion of this report that warrants a further explanation on some of the doctrine that relates to DNA profiling. DNA stores the information necessary for passing on our genetically determined attributes to children and children’s children, and this information is effectively the instructions necessary for being a living human. Every bit of information comes in double forms or two halves one bit is paternally inherited and the other is maternally inherited. Frequently, the two pieces of information are very alike, though they are not always the same, and the DNA in human cells also contains large stretches that contain no useful information, often referred to as junk DNA. It is worth knowing that the junk DNA that is dissimilar largely in a variety of people, and this is because it carries no useful information it is free to change without consequence. It may be useful to think of junk DNA as typos in a sequence of copied manuscripts and each copy of the manuscript will be ideally similar and carry the similar information, and despite the presence of typos in the copies of the manuscripts that will vary from one to another, connotatively implies from one person to another. If one knew what typos they drew in the copy of a manuscript then one could identify that copy of the manuscript. In an analogous fashion, DNA fingerprinting compares regions of the junk DNA from the crime scene evidence with DNA from a known individual and attempts to positively identify that person to the exclusion of anyone else. Much Like typos in a manuscript, the junk DNA can be very dissimilar in many ways, and the most noticeable is the size of particular features called short tandem repeats, which have mentioned in the text earlier. From an earlier an explanation, the STRs are areas where the DNA sequence are repeated, and the lengths of these repeats vary considerably from one individual to another; if one analyses enough of these STRs the individual from which the DNA originated can be discriminated very precisely. In DNA fingerprinting, 10 of these STRs are compared using a technique based on the polymerase chain reaction, which is simply a process for generating many of copies of particular regions of DNA, and for every STR the result is presented as one or two peaks on a trace, and are given a figure which represents the length of the particular STR. If one peak is seen then the DNA contains two versions of the STR which are of identical size, if two peaks are seen the alleles are of different sizes. Apart from just the information derived from the STRs, DNA fingerprinting can show the sex of an individual under the sample, and through the analysis of the amelogenin gene provides for the determination of the sex of a person, and it is one of the only genes that exists on the Y chromosome, which provides the clue for the male sex. It also exist on the X chromosome, even though the two copies of the gene are dissimilar, and when subjected to further analysis then the differences implies that males produce two peaks, as they have one Y chromosome and one X chromosome and then females produce only one peak as they have two identical copies. , According to Krawczak & Schmidtke (2002), forensic genetic fingerprinting is the comparison of the DNA in an individual’s nucleated cells with that recognised in chemico-biological matter recovered on the crime scene with the DNA of another individual for the sole reason of recognition or elimination. The use of these methods initiates novel factual verification to criminal and civil investigations and court cases. The use of DNA profiling found a sustained use in the late twentieth century, and its use gradually improved in criminal cases over the years. In later years, the evolution of the discipline unearthed the polymerase chain reaction (PRC), which further opened up the science to enable tests on even the smaller blood samples that were earlier impossible to test. This also made the technique of testing more time efficient and cheap and this was made possible with the establishment of national DNA databases in the UK for the sole purpose of cross referencing. The process of DNA profiling begins when DNA is isolated from samples of blood, semen, vaginal fluids, hair roots, skin, and skeletal remains. In the case under analysis the samples were taken from the blood samples recovered from the scene of crime. The Polymerase Chain Reaction (PCR) If there exist a small amount of DNA through the process known as PCR and the process does a DNA replication in a test tube (Bogusz, 2008). After the isolation of the DNA it is then augmented with PCR and treated with restriction enzymes, and then cut at specific sequences. From years of experiments, it is has been realized that every person’s DNA is different, and therefore every person’s DNA will be cut at different sites. Hence the results of two different DNA tests always comes out in different sized fragments, and the different sized fragments have been known as restriction fragment length polymorphisms (Fraser & Williams, 2009). Through this, it is observable that the dissimilar sizes of fragments in the experiment separates the DNA based on fragment size known as Gel Electrophoresis. Every person has genetic sequences and these are known as variable number tandem repeats, or simply given acronym VNTRS. Hence, each and every individual has dissimilar VNTRS, and the VNTRS comprise the different sized restriction fragment length polymorphisms. DNA Profiling Applied to his Case The first conclusion that can be made with respect to the SGM+ DNA proves that Hodgson was responsible for the near death on the scene as the traces of blood stain left recovered contains his DNA type. This was illustrated by two peaks that could be seen when analysing the from the electrograph samples of the knife and the head of the hammer and as they matched samples taken from Mr. Hodgson’s sock and Andrew’s sovereign ring these should be compared from the DNA taken from the victim. Hairs from the Hammer Hairs from Andrew’s Sovereign Ring Hairs from Hodgson’s Socks Reference Sample from Widdowson This means that Mr. Hodgson could have left his DNA on the victim while hitting him. Then, having in mind the SGM+ DNA profile this shows that the Andrew is responsible for the status the Victim is currently. Third, the reference sample obtained from Mr. Widdowson indicates that it must have indisputably Mr. Andrew as the DNA sample obtained from the Victim perfectly fits those from his sovereign finger. The current information available on their different ethnicities can help in quelling the notion behind who might be ultimately responsible: Mr. Hodgson is of an Afro decent and Mr. Andrew is Caucasian. Calculations that is based on the allele frequencies can show that there is a given likely hood that either of them was the main suspect in stabbing and hitting the victim with the knife and the hammer respectively. Calculations that are based on the allele frequency show that is a low likelihood that there is no chance that Mr. Hodgson committed the offence, from the samples taken from him and those of the suspect. Similarly, population show genetics show a similar low frequency, that there is a slim chance that another individual could have had a hand in the murder. Conclusion Given the excellent DNA profiles obtained using the well-characterized and proven SGM+ system and the subsequent statistical analysis it is my professional opinion that Andrew was the source of the blood stain found on the victims clothing. Statement of compliance As a forensic expert witness in this hypothetical it is important to represent this issue with integrity and to be above board, and to understand the duty of the expert witness to a court of law, hence such demands compliance with expected level of duty. This report includes all matters relevant to the issues on which my expert evidence is given, and the details in this report of any matters which might affect the validity of this report. These important issues have been addressed in this report to the hypothetical court. Statement of truth It is the belief of this report that the facts that have been stated in this report are true and that the opinions expressed are correct. Reference List Top of Form Bogusz, M. 2008. Forensic science. Amsterdam [etc.], Elsevier. Fraser, J., & Williams, R. 2009. Handbook of forensic science. Cullompton, Devon, Willan Pub.Bottom of Form Krawczak, M., & Schmidtke, J. 2002. DNA fingerprinting. Oxford, UK, Bios Scientific Publishers. Appendix modality NRC 4.4a product theta or F= 1/100 race c c c profile matching chance= 1/38.5e6 1/41.1e6 1/245 Locus Alleles Frequencies TPO 9 0.1298 0.01798 0.01685 0.3191 D3S1358 16 17 0.2239 0.2239 0.1002 0.1002 0.387 VWA 16 18 0.2037 0.2222 0.09053 0.09053 0.3791 DQAI 1•1 2 0.125 0.0913 0.02284 0.02284 0.3098 pYNH24 1684 1822 0.0607 0.0574 1/143.5 1/143.5 0.2813 Read More