The Importance Of Gunshot Residue As Evidence

The Importance Of Gunshot Residue As Evidence Gunshot residue is made of particles that form when gasses coming out of a gun hit a surface and instantly cool and condense. The presence or absence of gunshot residue can suggest whether a person fired the weapon or was the victim. There are many tests to show whether or not gunshot residue is present on a surface. The techniques and methods of testing have gotten much more scientifically advanced and more sensitive to minor details. There have also been many experiments to disprove the concerns of gunshot residue testing, such as false positives, transferability, and destruction of evidence. These facts alone disprove many of the arguments that gunshot residue is unreliable and should not be used as a source of evidence. Strengths and Importance of Gunshot Residue as Evidence in Court Cases Firearms are not a rare commodity in the United States, or the world for that matter, and so a basic understanding of what happens when the trigger of a gun is pulled is necessary. Many people know that when the trigger of a weapon is pulled the hammer strikes the back of the bullet casing, which ignites the primer, and creates pressure and heat in the barrel. This pressure buildup is what propels the projectile down the barrel and towards wherever the gun is pointing. The knowledge of what else comes out of the barrel and what happens with it that is not quite as well known. When the primer is struck, the intense heat causes the chemicals in the primer to vaporize and get mixed in with the gasses that are building up. When the projectile is pushed out of the barrel the gasses and the burning and unburned grains of gunpowder travel with the bullet. These gasses hit a surface such as the hands of the shooter, the victim, or surface that is being fired at. The gasses then condensate on the surface, leaving particles that are composed of the chemicals in the primer. This condensation of chemicals is referred to as gunshot residue, or GSR (Wolten Nesbitt, 1980). Gunshot residue has been used for many years as a source of evidence to not only suggest if a person has fired a gun or how far from a surface a gun was fired, but also if a case was a homicide or a suicide. However, there have been disputes over whether or not GSR is a reliable source of evidence. The points brought up in this argument are that gunshot residue tests can have false positives and false negatives, GSR can be transferred from person to person or surface to surface, and that test results can be different and sometimes inconsistent (Wolten Nesbitt, 1980). Over the years the methods of testing for gunshot residue have dramatically improved and become much more scientific. There are much less false positives due to the increased sensitivity of the tests. Research has been done that shows that even though GSR may transfer, investigators can still tell if a person fired a weapon, or just came in contact with it (DiMaio, 1999). There are also many other uses for gunshot residue analysis other then knowing if a person came in contact with a weapon, such as range determination (Saferstein, 2006). The purpose of this paper is to show the strengths and importance of gunshot residue analysis as substantial evidence in criminal court cases. Literature Review In the detection of GSR, DiMaio (1999) states that scanning electron microscope-energy dispersive x-ray spectrometry (SEM-EDX) has a much higher sensitivity because it uses a scanning electron microscope to view questionable GSR particles at a high magnification. Torre, Mattutino, Vasino, and Robino (2004) agree with using SEM-EDX because the technique can distinguish between GSR and brake lining particles. By using an adhesive lifting method the SEM-EDX is even more effective (Nesbitt, Wessel, Jones, 1976). Bird, Agg, Barnett, and Smith (2007) disagree with the use of SEM-EDX. They say that time resolved x-ray fluorescence should be used. On the topic of transferability of gunshot residue, Gialamas, Rhodes, and Sugarman, (1995) states that police officers are very unlikely to transfer GSR to suspects. Vinokurov, Zeichner, Glattstein, Koffman, Levin, and Rosengarten (2001) agree that GSR is not transferred or destroyed very easily with an experiment on the destruction of GSR due to machine washing or brushing. Havekost, Peters, and Koons (1990) state that the investigator also has to look at where the GSR is located on a person to tell if the particles have been transferred or not. Firing distance determination is a common factor in investigations. Saferstein (2006) states that using the Greiss Test method provides a more contrasted view of GSR on a surface. DiMaio (1999) states that using Greiss Test results can help determine whether a case is a homicide or a suicide. Brazeau and Wong (1997) say that using GSR tests can also help determine whether a bullet wound is an entrance or an exit wound. Discussion Detection Methods Gunshot residue detection tests first came to the United States in 1933 in the form of a paraffin test, which was used by covering the hands with paraffin wax and using a color-changing reagent on the wax. Swabs were used instead of wax starting in 1959, but in the 1980s neutron activation and flameless automatic absorption spectrometry (FAAS) were the methods used most commonly. The above methods were effective for the detection of the three main elemental components in GSR, antimony, barium, and lead, but came up with many false positives and negatives (DiMaio, 1999). The occurrence of false negatives and positives is one of the main reasons that gunshot residue is sometimes considered a risky or an unreliable source of evidence. Since the previous tests only tested for the presence of barium, antimony, and lead, any other substance including those elements had the potential to give a false positive result. Defense attorneys could use these false positives as defense tactics to suppress evidence. In the late 1980s a new GSR test, scanning electron microscope-energy dispersive x-ray spectrometry (SEM-EDX), started to be used. SEM-EDX has a much higher sensitivity, because this technique uses a scanning electron microscope to view questionable GSR particles at a high magnification and look at the size and shape of the particles. After particles are found under the microscope, x-ray waves are used to identify the elements on and inside the particles (DiMaio, 1999). Since SEM-EDX allows a person to look at the size and shape of a particle, GSR particles can be distinguished from other environmental or chemical particles that may also appear on the tested surfaces. Being able to differentiate between sources of particles diminishes the false positives to a very few occurrences, if any. This also means that gunshot residue tests and results cannot be as easily disputed in court. The theory of having less false positives has been tested on different occasions to show that using SEM-EDX makes GSR tests more reliable. Research by Torre et al. (2004) shows the results of tests involving particles and residue from the hands of people who work with automobiles. Particles from the brake linings and other moving parts of a car contain barium, lead, and antimony similar to GSR. This experiment proved that SEM-EDX successfully differentiates between gunshot residue and automobile particles using blind tests, which are tests where the person running using the SEM-EDX does not know where the sample came from (Torre et al., 2004). Other tests and experiments included testing to see if SEM-EDX can differentiate between leaded gasoline, which has particles most similar to GSR, and gunshot residue. The experiment was also done in a blind test fashion and was completely successful in further proving the reliability of SEM-EDX (Nesbitt, Wessel, Jones, 1976). Another positive benefit of the scanning electron microscope tests is the methodology of the collection of the samples that was used. Instead of swabbing the hands an adhesive lift is used (Nesbitt et al., 1976). Since an adhesive lift collects the particles in their relative spots it is possible to determine the ratio of particles in a particular surface area. This gives a more accurate distribution and concentration ratio than swabbing a surface and analyzing the number of particles on the swab. The scanning electron microscope-energy dispersive x-ray spectrometry method allows a much longer testing window from the time the gun was fired. With SEM-EDX positive results can be received up to twelve hours after the shooting (DiMaio, 1999). This is because SEM-EDX combines visual inspection of individual particles as well as a mass calculation of the elemental concentrations. There is also another test that can have positive results for as long as thirty-six to forty-eight hours after the gun was fired. This is done with the trace metal detection technique (TMDT), which uses reagents that change colors under a ultraviolet light after they have come in contact with the elements in GSR (DiMaio, 1999). With the newest technological advances, x-ray fluorescence microscopy allows for an even more precise look at GSR particles. This method uses the excited state of particles due to x-rays and investigators observe these particles underneath high powered microscopes. The particles fluoresce and appear brighter then the surface (Bird, Agg, Barnett, Smith, 2007). The fluorescing particles make the visualization of GSR particles much easier and allows for a more specific determination of the spread of the residue. Destruction and Transferability Some people may say that allowing more time to pass between the firing of the weapon and when the sample is collected is a detrimental thing. The extra time allows people to wash their clothes or hands or try to at least wipe them off. This is another point argued by people who say GSR is unreliable. There is always the possibility that a suspect can wash their hands and clothes after firing a weapon. The fear is that once that has been done that there will no longer be particles left to detect. In the experiment published by Vinokurov, et al. (2001), tests were done on clothes that had been machine-washed and other tests on clothes that had been brushed with another piece of material. The tests showed that even though a majority of the GSR particles had been removed, there were still enough particles in some circumstances to get a positive GSR detection (Vinokurov, et al., 2001). The results of this experiment proved that even though investigators may allow more time before testing, there are still chances that investigators can get results even after evidence is washed. Besides washing clothes and hands, there is also the possibility that GSR particles can be transferred to another person or surface by direct contact, or if a person is within a close distance when a gun is fired. Gunshot residue is easily rubbed off or transferred to someone else, which sometimes can make deciding what really happened difficult, but not impossible. Even though gunshot residue can be found on a person who did not fire a weapon, there will be certain circumstances in order to prove they didnt fire the gun. A person standing within a close range can have GSR on them. Although a person will test positive the location of the GSR and the concentrations will be different then if that person pulled the trigger and fired the weapon. For instance, if a person puts their hand out in self-defense of a shooter, there will be residue found on the palm of the hand in but very little if any on the back of the hand. If the person fired the gun, there would be a high concentration on the back of the hand (Havekost, Peters, Koons, 1990). Another situation is one that has been argued by defense attorneys. Defense attorneys say that the GSR that was found on the suspect could have been transferred from the hands of the police officer that arrested them. In theory, this may sound possible, but most officers do not even touch their gun on a daily basis, let alone fire it. In a study published by Gialamas, Rhodes, and Sugarman (1995) police officers that had not fired their weapon over a certain period of time were tested for gunshot residue. Forty-three officers were tested, and out of those officers twenty-five showed absolutely no particles that even resembled GSR. Seventeen officers were found to have particles similar to GSR, but were only environmental contaminates, and three officers were found to have only one particle of GSR (Gialamas, et al., 1995). Even though a couple of the officers showed a particle of GSR, there would have to be a much higher concentration of particles in order to conclude that that officer had fired a weapon. Even if the officer had a GSR particle on them, although possible, the likelihood of touch transfer is extremely small. Even if that particle did transfer when an officer touched a person, the particle would be in a place inconsistent with firing a weapon, such as the shoulder, wrists, back of the neck, etc. Range Determination Gunshot residue analysis can be used for purposes other then determining if a suspect was holding the gun that was fired. Gunshot residue can be used to determine how far away from an object the gun was when it was fired. This is done by the GSR pattern left on the surface of the target. There are other tests that can be used to better develop and lift the residue pattern from a surface. One of the methods that can be used is the Greiss test. This test involves the use of a chemically treated gelatin-coated photograph paper. The paper transfers the residue pattern by reacting with the nitrates in the gunshot residue. After the pattern is transferred off of the target surface test fires are done to match the spread and distribution of the GSR and determine the relative distance of the shooter (Saferstein, 2006). Since the Greiss test can be used on clothes and other target surfaces this technique suggests that gunshot residue is very valuable in the determination of distance. Using gunshot residue as a distance determination can also help determine whether the case is a homicide or a suicide (DiMaio, 1999). Sometimes a homicide can be staged to look like a suicide, usually by placing the gun in the hands of the victim. By using the gunshot residue pattern to determine the distance of the weapon when fired, investigators can tell whether or not the victim was holding the weapon. It is only physically possible for a human to hold a gun aimed at themself a certain distance away from their own body and still be able to pull the trigger. This distance is directly related to the victims arm length. If the range determination suggests that the distance between the victim and the gun was much greater then the victims arm length, then the crime was more then likely a homicide (DiMaio, 1999). Gunshot residue cannot only be used to determine the distance that the weapon was fired at, but also whether or not a wound is an entrance or an exit wound. A GSR test can be done on the edges of the wound to see if there is residue present (Brazeau Wong, 1997). A medical examiner may need help determining whether a wound is an entrance or an exit in a couple of circumstances. Sometimes a bullet can ricochet off of another object before hitting the target, which can cause the wound to look different then the normal entrance wound. The medical examiner may also consider using a GSR test to determine if the wound is an entrance wound if the projectile has entered and exited the body multiple times due to the way the victims body is positioned (Brazeau Wong, 1997). Another use of gunshot residue tests around the edges of a wound is to see if the wound is in fact from a firearm. Sometimes wounds can look like a gunshot wound but are actually from other sources. One of the sources for wounds that can appear as a gunshot wound is the hole some insects will make while they are feasting and laying eggs on a dead body (Brazeau Wong, 1997). Conclusion There are no two cases that are completely and indisputably the same. That is why each case has to be looked at individually. Investigators need to take the time to evaluate the results of any tests and evidence, including gunshot residue. Just because a gunshot residue comes back negative does not necessarily mean there was never and residue there. The same goes for a positive result, just because a test comes back positive does not necessarily mean that that person was the shooter or held the gun. With all the new advances in the technology used to test for gunshot residue the downfalls and errors previously associated with GSR have almost completely been eliminated. Many different studies and experiments have disproved many of the concerns over the tests and results of GSR tests being unreliable. GSR also has many other helpful uses in solving cases such as distance determination and the difference between a homicide and a suicide. While gunshot residue may have been made out to have many downfalls and disadvantages, and while it is not absolutely accurate, nothing in the scientific world is absolutely error proof, and therefore GSR is extremely helpful and is reliable enough to be considered substantial evidence not only in cases but also in court.

Between The Forest And Greed :: essays research papers

Between The Forest and Greed Within the past decade there has been a rising "environmentally conscious" movement. The spectrum of issues in contention by environmentalism has expanded virulently and is reaching its zenith. Public dissatisfaction with the environmental movement is forming, as the movement has taken the fight for the environment too far. Donella Meadows is an environmentalist who has yet to fully think about the issue she is arguing. In her piece "Not Seeing the Forest for the Dollar Bills," she takes an almost infantile approach to the logging industry and the concept of clear cutting. The monetary motivations behind the logging industry is her explanation for clear cutting, trying to portray the logging industry as a cold money making machine. This of course neglects the fact that the reason logging generates capital is because the world needs wood. There are several economic and environmental issues that are considered when loggers enter and area. Haphazard clear cutting of forests, while it maybe what Meadows would like us to think, does not happen. With every industry, every aspect is carefully debated and analyzed for the short and long term outcomes. Any industry that capitalizes on earth's resources figuratively signs a pact with the earth. This pact bonds this industry to the earth and requires that any harvesting of resources is not done so with haste and waste. There is a symbiotic relationship between the two. For the industry to exist there must be a constant supply of the resource. Without a constant supply the industry dies. Now, many people believe that the logging industry's objective is to cut down all the trees that are currently standing. As horrific as this scenario may sound, it is far from the truth. Without trees to cut down there is no industry. The logging industry is not so foolish as to rampage the forests and cut down all the trees. As they cut, they plant. Replacing forests with samplings may look inadequate, but over a long period of time these samplings will become a new forest. The earth as we know it today has been in existence for millions of years. Even if newly planted tress take a century to grow back that is only a pinpoint on the time line. The millions of acres of forested land left untouched currently will not be engulfed by blades and tractors instantly. It will take time to cut down the trees, as it will take time to grow them back. Meadows seems to have a misconception of industries and the service they provide. All industries, whether it be recycling to logging, are trying to

Assessment and Child Essay

Assessments are very important in determining how to teach our children and where they are in terms of development. There are many types of assessments that can be beneficial in helping determine how to approach the learning style of each child as an individual instead of as a whole group. While each assessment is structurally different, they can produce results which give us insight on where our children are during different stages of their lives. There are both formal and informal assessments that can be used. â€Å"Formal assessments are norm-referenced tests that have standardized, formal procedures for administering, timing and scoring. They have been â€Å"normed† or administered to a representative sample of similar age or grade level students so that final test results can be compared to students of similar characteristics. Test results indicate a person’s relative performance in the group. These standardized tests must be administered as specified in the manual to ensure valid and reliable results†(ERIC Clearinghouse on Assessment and Evaluation). There is another type of formal assessment called criterion-referenced test. These type of test measure what the person is able to do and indicate what skills have been mastered. A CRT compares a person’s performance with their past performances. â€Å"In criterion-referenced measurement, the emphasis is on assessing specific and relevant behaviors that have been mastered rather than indicating the relative standing in the group†(ERIC Clearinghouse on Assessment and Evaluation). Formal assessments can prove to be beneficial as far as comparing test scores over a period of time and how the child is developing over that same period. While formal assessments are useful they also have flaws in them. Standardized test can make a child feel like pressure and anxiety. In a lot of situations when a child feels like this they will not do their best on any type of assessment. Another problem with these types of tests is that they use the same set of questions for all the children and are not sensitive to the situations that different children endure. Children who live in poor and underdeveloped environments may not be exposed to certain ways of life and may not have the same advantages of acquiring knowledge as the other children they go to school with. This will automatically put them at a disadvantage in school and on test they may take. There is another way to do an assessment that is better suited for the child and does not make them feel so uncomfortable and that is an informal assessment. An informal assessment focuses on play and observation of the child and not a test of sorts. By observing the child in a certain situation you can record how they act and how they respond to different situations and stimuli that are presented to them. You can use check-list and rating scales to record your findings and document them and file them away in a portfolio. Another way to do an informal assessment is by parent interviews. You can find out a lot of valuable information by asking the parents questions about their child. Over the past few years teachers have placed more emphasis informal testing than formal testing. â€Å"Some districts have increased the use of curriculum-based measurements(CBM). Several samples of a student’s performance are collected, using items drawn from the local curriculum, usually in basic skill subjects of reading, math, spelling and written expression. Such brief tests are called â€Å"probes†(ERIC Clearinghouse on Assessment and Evaluation). One form of an informal assessment is the Battelle Developmental Inventory. â€Å"The Battelle Developmental Inventory is an assessment for infants and children through age seven. It is a flexible, semi-structured assessment that involves observation of the child, interviews with parents and caregivers, developmental and social history, and interaction with the child using game-like materials, toys, questionnaires, and tasks† (Logsdon). This type of assessment is used to make sure that infants and children are reaching their developmental milestones or showing early signs of learning disabilities or developmental delays. This assessment can also be used through examiner/child and parent/child interaction. Examiners observe the child’s responses and score them based on standardized criteria. The parent caregiver input is also important in the assessment because it is used to gather information about the child’s history and interactions that take place beyond the testing session. When this assessment is used to observe the toddler through preschool development it is mostly done by tasks that involve testing the child with games, toys and tasks. They observe how the child follows directions, interacts with others, and how they perform certain tasks. Parent information is used to assess areas that can’t be observed during the testing session. The performance scores are based on standardized criteria. The Battelle is used to assess five components of development. They are adaptive behavior, personal and social skills, communication including expressive and receptive language, gross and fine motor skills, and finally cognitive skills are included. The results of this assessment can be used to determine if there are delays and how significant they are based on the age group the child is in. Another good assessment tool is play-based assessment. This is simply observing the child in their natural environment. By doing this the observer is able to see interactions between the child and their peers as well as how they speak, the language they use and their motor abilities. It is good to record all this information and keep it in an ongoing portfolio. By keeping a written record of what has been observed and any areas of concern you may suspect, you will have more information to share with the parents and find the proper method of dealing with the problems. I feel there is a major advantage when you use an informal assessment as opposed to a formal one. With formal assessments you can never really tell how smart a child really is. These types of assessments are based on statistics of a large group of children not the children as individuals. Just because children do well on a test does not necessarily make them smarter than others, it simply means they have better test taking skills. There are lots of times that the smartest people do horrible on tests just because they suffer from anxiety and get nervous. You can take the same kids that do poorly on a test and give them an informal assessment where they feel comfortable and you will get different results. Standardized tests are not a reliable means of assessing intelligence based on the fact stated above. These types of tests are often overused in this country and they do not take into account the comfort level or socioeconomic background of the child being tested. These play a more important role in test taking than the test itself. This is the number one reason kids are misdiagnosed for having  learning disabilities and other disorders such as ADHD. I also feel that a good relationship with the parents is essential in determining the educational needs of the child. No one knows their children better than the parents or caregivers. They are the ones who spend the most time with the children and can fill you in on patterns of behavior not seen during a certain test taking session. Parents are the most important resources you can obtain information from when dealing with children. I would strive to keep the parents informed of everything that was going on with their child and how to help them with anything that raised a red flag. The parents should always be informed when an assessment is going to be used. A parent could be upset when their child is going to be tested for a development problem without their consent. If you explain the process and how it can help to determine if the child is developmentally behind it can ease the parent’s mind and make everyone more comfortable. I feel that assessments can be beneficial if they are conducted in the proper manner. Making a child feel more comfortable in their environment is the best way to truly assess them and find out if they are lagging in certain areas of development. It is equally important to always keep the parents involved in all decisions affecting their child and the processes used to assess them. The information used by assessments can help make sure children are developmentally on track, just remember the most important factor is the comfort level of the child. Without assessments a plan of action cannot be implemented or executed if the child is behind in any facet of development. Bibliography Logsdon Ann. Testing for Infant and Toddler Development. About. com Guide. http://learningdisabilities. about. com/od/intelligencetests/p/battelledevelop. htm. Accessed on December 10, 2012. ERIC Clearinghouse on Assessment and Evaluation. Assessments for Young Children. 1999. http://www. 1donline. org/article /6040/ Accessed December 10, 2012. Sue C. Wortham (2012). Assessment in Early Childhood Education. 6th ed.

Essay on Cockroaches in the College Dorms - 1495 Words

Cockroaches in the College Dorms Our dorm is populated with more than 150 students from all parts of the country. However, humans alone do not make up most of the population of the dorm. Cockroaches live year round in the humble abodes of many college freshmen. Walking through the halls of the dorm, finding evidence of their residence is very easy. Most of the time, there are squashed ones in the halls and on the sidewalks leading to the dorm. Something must be done in order to keep the roaches from taking over completely the male dorms. It is well known that Smith dorm is probably one of the most disgusting dorms on The college’s entire campus. This is partially aided by the fact that the students do not live alone.†¦show more content†¦Piles of dirty laundry, crumbs on the ground, and even old mattresses all seem to be just part of the normal dorm experience. However, to a cockroach, this seems like heaven on earth. With the warmth provided by the piles of laundry and even just the temperature of the room, it is no wonder that once these bugs find their way into the room, they do not want to leave. College students also seem to be the worst about cleaning up after themselves. A student grabs a snack after class and does not realize that he or she had dropped crumbs all over the room. Months go by before anyone vacuums. It is no wonder the roaches love the dorm. They have an endless supply of food and warmth. However, they absolutely must have a supply of water or they will die within days (New Jerse y 2). Once infected with roaches, how does one go about getting rid of these unwanted pests? The answer sounds simple enough, but actually attaining the desired results may be a bit harder. If the roaches are simply looking for warmth, food and water, it follows that getting rid of the water supply and food source would be enough to rid the bugs for good. Things as simple as taking out the trash, eating only in one designated place, and sealing all uneaten foods in air tight containers are all ways of dealing with their source of food. Getting rid of their water supply is harder, especially at The college. The most obvious location for a supply of water in the dorms is the