Touch DNA is the method of analyzing skin cells from an assailant left behind at a crime scene.1 The United Kingdom was the first to use it as a method in evidence collection in 1999.2
The process of touch DNA was fist demonstrated in 1997 and since then has been extremely useful in criminal cases. The United States adopted this method of analysis in the year 2003. Though it was first used only about 15 years, in the past few years it has been used more. The use of touch DNA has grown more popular because there is no visible evidence needed. With other common forms of DNA collection, the evidence needed, for example blood or semen, must be visible in order to collect a sample.3 On average, a sufficient amount of DNA would need to be the
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Multiple methods have been studied and tested. When collecting touch DNA samples, there is little training required.2 A evidence technician or a crime scene specialist is not mandatory in collecting touch DNA evidence.2 Swabbing and tape lifting are the two major types of DNA evidence collection. With many studies, different forms of tape lifting were tested. In one study in particular Scotch Magic and Scenesafe FAST were tested against each other. It showed that the Scenesafe tape was more effective in collecting DNA profile evidence. In the study one of the factors that was tested was the adhesion of the tape.5 The tape was effective in collecting DNA sample, but one problem with the tape was it was difficult to remove a profile from the surface of the tape. Even with this, the profile results outweighed the problem.6 A different study tested the effectiveness of synthetic swabs compared to cotton swabs and a mini tape method. After the study, it was concluded that while there was no significant different between the swabs, there was a difference between the swabs and the tapes.8 The minitapes did show a complete DNA profile for all samples tested. Overall this study showed that minitapes are more successful for collecting small traces of DNA than any types of swabs.8 With all of the studies on which method is more effective, there are still some occasions where swabs work best. It was also found that a touch DNA kit …show more content…
For example, at crime scenes where a firearm is present, there is a specific procedure that is followed with the collection of that piece of evidence depending on which agency is in charge. One step in the procedure is to test the firearm for fingerprints.9 When checking for fingerprints, the analyst need a suitable print. A print is considered suitable when it is high quality and the ridge marks are visible. Also the picture of the print will be acceptable to compare with other prints on a database.4 When collecting fingerprints, there are only two possible options, a suitable print or not. With only those two options for firearms fingerprinting, it is difficult to limit the list of suspects during a case. Crime labs are now swabbing firearms collecting touch DNA. Deciding between fingerprinting and collecting touch DNA is important. Using the fingerprint process involves multiple people handling a firearm, slowing destroying the traces of DNA evidence.9 If the DNA process is chosen, the moist swabs will destroy any fingerprints that are on the firearm.9 DNA profiles can be partial or complete and both are successful.4 Fingerprints only have one possible successful outcome, a suitable image.4 It is possible to find a partial fingerprint, but with the partial print, you can match with multiple subjects. If a full DNA profile is obtained, that has the highest potential value.4 Even
In certain situations, it is necessary to identify DNA retreived from a sample. When there is a
The analysis of the samples should be used only to confirm or negate match between the sample taken from the crime scene fgand the sample taken from the suspect. That is, it should sdfremain as an identifgication tool only. There should be no further analysis of the DNA to suggest psychological characteristics that would make the suspect more likely to have cdfommitted the crime. This rule should apply also to samples taken from convicted dfdoffenders for a data vor dagta bank.
. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique, there has been a large number of individuals released or convicted of crimes based on DNA left at the crime scene. DNA is the abbreviation for deoxyribonucleic acid.
Nowadays, DNA is a crucial component of a crime scene investigation, used to both to identify perpetrators from crime scenes and to determine a suspect’s guilt or innocence (Butler, 2005). The method of constructing a distinctive “fingerprint” from an individual’s DNA was first described by Alec Jeffreys in 1985. He discovered regions of repetitions of nucleotides inherent in DNA strands that differed from person to person (now known as variable number of tandem repeats, or VNTRs), and developed a technique to adjust the length variation into a definitive identity marker (Butler, 2005). Since then, DNA fingerprinting has been refined to be an indispensible source of evidence, expanded into multiple methods befitting different types of DNA samples. One of the more controversial practices of DNA forensics is familial DNA searching, which takes partial, rather than exact, matches between crime scene DNA and DNA stored in a public database as possible leads for further examination and information about the suspect. Using familial DNA searching for investigative purposes is a reliable and advantageous method to convict criminals.
Another discrepancy between actual forensics and how it is portrayed in the media is the availability of information in databases. There is only a small percentage of the entire population’s fingerprints or DNA samples stored within databases such as the Integrated Automated Fingerprint Identification System (IAFIS). This makes finding a match between a DNA sample or fingerprint difficult, as a match would only be found if the person’s information was already stored within the database. If there is no match previously stored in a database, the fingerprint or DNA sample could be potentially rendered useless within a trial. Typically, in order to perform an analysis, investigators must already have a suspect in mind and request a DNA or fingerprint sample from him or her. If the suspect does not want to provide one however, the sample collected as evidence may not count as valid. The CSI effect creates an idealized image that all crimes can be solved with a hair or drop of blood, but this is not always the case in real life.
Abstract; This paper explors the effects DNA fingerprinting has had on the trial courts and legal institutions. Judge Joseph Harris states that it is the "single greatest advance in the search for truth since the advent of the cross examination (Gest, 1988)." And I tend to agree with Judge Joseph's assertion, but with the invention and implementation of DNA profiling and technology has come numerous problems. This paper will explore: how DNA evidence was introduced into the trial courts, the effects of DNA evidence on the jury system and the future of DNA evidence in the trial courts.
Contextual information also affects the human comparative part of fingerprint analysis, in ways that alter the matching of the same fingerprints, years apart; however, when contextual information is provided, it actually helps 20% of forensic technicians, but that still leaves 80% hindered by contextual information (Dror et al, 2006). Contextual information affects the psychological aspects of perception and problem-solving, in a way that can obscure information that does not support the context, and it can even affect how forensic technician’s view and handle forensic evidence (Bernstein et al, 2013). However, there are some advantages of contextual information, because it can give the forensic division a mental shortcut, saving time and money; however, these shortcuts lead to inaccurate and biased conclusions. This essay has shown that contextual information creates erroneous mistakes and prejudiced results in forensic investigations. A possible way to remove the negative effects of contextual information is to have the forensic technicians, not know the context of the crime so that they do not
First and foremost is the Michael Mosley case. Michael Mosley was convicted murdering a couple ten years ago (Wurtman, 2011). Two other men were cleared when Mosley’s DNA was found at the scene of the murder (Crowe II, 2012). Also, there was a palm print on the wall and further DNA on the sheets in the bedroom (Wurtman, 2011). In contrast to all the evidence, Mosley’s attorney offered an alternative reason and painted a picture of different events to explain Mosley’s DNA’s presence (Wurtman, 2011). However, the jury didn’t buy the defense’s story, and Michael Mosley’s conviction led to a call for the DNA database to be worked on with the most interesting fact being that Michael Mosley had no DNA in the system until seven years later than the crime (Crowe II, 2012).
DNA fingerprinting, or sometimes known as DNA typing, is isolating and developing images of sequences of DNA to evaluate the DNA in an individual’s cells. DNA fingerprinting today is used for many different things in many different areas of science. In forensic science, DNA typing can determine which person did which crime by using blood or skin left at a crime scene. In medical science, patients can find out who their siblings, parents, or children are by using DNA fingerprinting (webmd).
The criminal justice system has changed a lot since the good old days of the Wild West when pretty much anything was legal. Criminals were dealt with in any fashion the law enforcement saw fit. The science of catching criminals has evolved since these days. We are better at catching criminals than ever and we owe this advancement to forensic science. The development of forensic science has given us the important techniques of fingerprinting and DNA analysis. We can use these techniques to catch criminals, prove people's innocence, and keep track of inmates after they have been paroled. There are many different ways of solving crimes using forensic evidence. One of these ways is using blood spatter analysis; this is where the distribution and pattern of bloodstains is studied to find the nature of the event that caused the blood spatter. Many things go into the determination of the cause including: the effects of various types of physical forces on blood, the interaction between blood and the surfaces on which it falls, the location of the person shedding the blood, the location and actions of the assailant, and the movement of them both during the incident. Another common type of forensic evidence is trace evidence. This is commonly recovered from any number of items at a crime scene. These items can include carpet fibers, clothing fibers, or hair found in or around the crime scene. Hairs recovered from crime scenes can be used as an important source of DNA. Examination of material recovered from a victim's or suspect's clothing can allow association to be made between the victim and other people, places, or things involved in the investigation. DNA analysis is the most important part of forensic science. DNA evidence can come in many forms at the crime scene. Some of these forms include hair; bodily fluids recovered at the crime scene or on the victim's body, skin under the victim's fingernails, blood, and many others. This DNA can be the basis of someone's guilt or innocence; it has decided many cases in the twentieth century. As the times continue to change and the criminals get smarter we will always need to find new ways to catch them. Forensic science is the most advanced method yet, but is only the beginning. As the field of science grows so will the abilities of the
Once a crime has been committed the most important item to recover is any type of evidence left at the scene. If the suspect left any Deoxyribonucleic acid (DNA) at the crime scene, he could then be linked to the crime and eventually charged. A suspect’s DNA can be recovered if the suspect leaves a sample of his or her DNA at the crime scene. However, this method was not always used to track down a suspect. Not too long ago, detectives used to use bite marks, blood stain detection, blood grouping as the primary tool to identify a suspect. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique it has been a la...
Deoxyribonucleic acid (DNA) is an acclaimed extraordinary discovery that has contributed great benefits in several fields throughout the world. DNA evidence is accounted for in the majority of cases presented in the criminal justice system. It is known as our very own unique genetic fingerprint; “a chromosome molecule which carries genetic coding unique to each person with the only exception of identical twins (that is why it is also called 'DNA fingerprinting ')” (Duhaime, n.d.). DNA is found in the nuclei of cells of nearly all living things.
"Using DNA to Solve Crimes." U.S. Department of Justice: National Institute of Justice. (September 9, 2014). Web. 29 May 2015.
The typical patterns of genetic profiles are produced by electrophoresis of treated samples of DNA. This patterns may be called fingerprints. In criminal investigations, there are tested about 10 sites of the DNA. If the banding patterns produced by the tested DNA samples of a suspect in a crime, and the samples taken from the crime scene are the same, it is enough evidence for convicting a suspect and taking him to jail. The 99% of human DNA is exactly the same for all the people, even though, a single droplet of blood, or an eyelash collected in a crime scene, contains all the genetic information needed of every single person in the world, to convict a criminal. DNA profiling has have a huge impact in many things, from the...
In fact, 1 Nano gram or less can produce unexceptional information to find a suspect or a victim of a crime. By means of this technology an investigator can extend their criminal investigation beyond the realms of traditional semen or dried up blood. Crime scenes may consist of less valuable DNA, it subsequently depends on the environmental conditions where the DNA was found. For certain, a sequence of factors ramifies the capability to obtain a pleasing DNA profile. By any means, extended exposure to any type of biological evidence can degrade the DNA, and therefore renders it useless for further analysis.