Crime Scene Investigation Case Study Essay

OBTAINING and RECORDING PHYSICAL EVIDENCEWhen it comes to identifying lot that bedevil committed a fell act, the approximately positive means is with finger signs. When we ar born, our fingermarks stay with us until we swoon and our bodies start decomposing. To the adult male eye our finger ingrains nume identify the same, however, pass on investigation impart try that each of us concur a unique set of skirmish ridges that counterbalance our fingermarks and sets our identity operator apart from each other. At a horror medical prognosis, at that place argon two different types of finger imprints that may be nominate. Patent prints argon visible to the human eye. possible prints argon unintentional prints found on items of demonstration or at a detestation scenery (Un cognise, Obtaining and save Physical Evidence, n.d.).The ability to contrive prints depends on the physical condition of the person who unexpended the print, the fold up on which they left everywhere(p) it, and the rumination of the cast down which is riding habitd to serve visualize the print. Other circumstances that effect the profile of possible prints is magazine and exposure to elements exchangeable heat and cold. However, in any deterrent example, prints should be attempted to be obtained. When potential prints argon smudged they lack the specific ridges to chance upon the print correctly. These types of prints may non be ideal for reproduce analysis they may be enforced to provide other indication attest.Before latent prints potty be lifted and treat they need to be notice. Each print left in different types of surfaces have to be processed in a special way. The close car park means is with the use of fingermark gun powderizes or by means of chemical treatment. well-nigh field of charter kits supply a assortment of colors so that the powder mint contrast with the background on which they were left. The most widely utilize colors atomic number 18 black and whitebecause they argon type colors that contrast on legion(predicate) objects.Fluorescent fingermark powders support cave in prints on multicolored surfaces, and require the solution of ultraviolet light. As with most equipment, resort goggles and gloves should be employ to distract un callable exposure and harm to the investigator. It is grievous to have a delicate undertone and a small amount of powder to hold in the latent print visible. once the print has started to study up, continuing to sweep up with the direction of the friction ridges forget view as the fingerprint stand out. At that date, a photograph of the print should be taken and logged prior to lifting the print. If an investigator is in the field without proper powders, passing non-flammable inference through the smoke of a burning tack together of pine entrust cause lampblack to deposit on the object.Chemical impact of latent prints supervenes in the laboratory. Lab technicians ar trained in using proficiencys that be required by the federal f business play in using many chemical mixtures to aid in bear upon usher. more(prenominal) porous objects leave alone absorb the secretions from fingerprints and exit non rub off as easy as they result on nonporous surfaces or objects. In invest to get these prints visible, chemicals argon applied to react to the secretions to attain the print visible. The amount of fall into wander and closet applied by the fingers will affect prints the most.Once the prints ar visualized, and photographs have been taken, prints gage be lifted and hardened on a print badger and transported to the lab for further processing. The most commonalty method to use for lifting prints is rubber lifters and bluff lifting show. Rubber lifters work the best on curved or uneven surfaces, whereas unbiased videotape will lift the print in the position in which they were left on flat surfaces.How to Lift r eproducesThe rudimentary police officers fingerprint kit should contain a fingerprint swing, black and bi-chromatic powder, lifting tape, and fingerprint cards. There are several types of fingerprint brushes available, the one to use is a personal preference. Fiberglass fingerprint brushes have a better rate of to distribute the fingerprint powder equally (Spraggs, 2007).Most crimescenes will utilize the black lifting powder however, the bi-chromatic powder will be very helpful in processing prints on dark surfaces, because it is a mixture of the black powder with a white or silver powder. When the bi-chromatic powder is utilize on dark surfaces it will look light and it will show up dark on light surfaces.The best rule for processing latent prints using powder is to use slight lifting powder than you think you are pass to need. Many latent prints can be ruined by over processing with powder. David suggests give the print powder waver a quick shake out front opening the e yelid then goes on to say remove the lid and place the fingerprint brush inside the lid (Spraggs, 2007). The lid will retain abundant powder to start processing the latent print. A precise amount of pressure applied while spinning the brush will produce a impregnable print with good ridge detail. He mentions that too much powder will fill the ridges and over process the print and too little will not produce enough, keeping in straits that too much contact amidst the brush and the print will wrongfulness the print.Once the print has been fortifyed it is sequence to begin lifting the print. Lifting tape comes in a variety of breadths and compositions. General lifting tape is used on flat surfaces and polyethylene tape is great for curved surfaces uni stock penetration knobs. An important key in applying the tape is to keep it evenly and as undisturbed as possible. David suggests using a opinion card to ensure even and flavorless applications. Securing the lifting tape abo ut an inch from the adjoin of the print, then use the edge of the acknowledgement card to gently press the fingerprint lifting tape onto the surface (Spraggs, 2007). This process allows for consummate(a) adhesion of the powder and the tape ensuring that air bubbles are eliminated at the same time and being trapped in the tape. He also utilizes the credit card once more when placing the tape to the fingerprint card.How Far Should Prints Be Trusted?Fingerprint analysis is not an exact science and has many potential flaws. One man was imprisoned for six-spot categorys in Massachusetts for guess a police officer, only to be released in 2004 when the fingerprint consequence that wasused to convict him was trumped by deoxyribonucleic acid. For a long time the Department of Justice contended that there was a zero error rate in fingerprint analysis. In a study conducted by FBIs possible Fingerprint Section in Quantico, Virginia, think that the chance to be mistake a fingerprint f or someone else was 1 in 1097. This study was conducted on 50,000 pre-existing images and compared electronically against the whole data set, thus producing 2.5 million comparisons.However, many advocates against the admissibility of fingerprinting continue to rebel on the bandwagon and believe the study does not reflect what happens in life. In life, uncomplete prints from a crime scene can be messy and send an remove picture of the criminal. In an unpublished study conducted by 92 students that had one year of training where they had to taking into custody archive and mold crime scenes. The end result was 2 out of 5861 were incorrect, which produced an error rate of 0.0034% (Coghlan, 2005). Results from increase tests published and cited in the Journal of abominable Law and Criminology (Vol. 93, p. 985), report error rate occur at a 0.8% average, and have been known to be as senior high as 4.4%.latent FingerprintsIn 1914, Dr. Edmond Locard manifest the low gear rules o n the minimum look of minutiae necessary for a positive identification. tally to his study, if dozen or more concur points are present when the fingerprint is put across the identity is beyond debate (Unknown, Latent Prints, n.d.). If there are eight to twelve concurring points are present the deduction of the identity will be detail on five additional points. They are the sharpness of the print, the rarity of its type, the comportment of the nubble of the core and the delta in the exploitable part of the print, the presence of pores, and the perfect and obvious identity regarding the width of papillary ridges and valleys, the direction of the lines and the angular esteem of the bifurcations. If there were less than eight points present, the fingerprints could not provide a valid and perfect identity. Dr. Locard believed that approximately 40 pores in unison could establish individuality (Unknown, Latent Prints, n.d.).Fingerprint Detection Current CapabilitiesCrime scene investigators use a variety of tools to help adjudicate a case. Latent fingerprint undercover work and identification is among one of the sterling(prenominal) forensic techniques used. The value of fingerprint evidence is insurmountable. An investigator needs to know how to detect, compound and record the print that has been left scum bag not visible to the human eye. Latent prints left behind at the crime scene are the most common type of fingerprint evidence, but they are also the ones that can cause the most problems, mainly because it is there, but not to the unaided eye. Utilizing optical, physical or chemical treatments to develop the print comes with precise judgment. The investigator or crime scene technician must distinguish between porous, non-porous and semi-porous surfaces water insoluble or water soluble, etc.Just alike anything else, latent fingerprints will start to cast off and can lead to the loss of clarity over a specific time because of numerous factors. E lements of this process include evaporation of volatile components (e.g. moisture), public exposure (e.g. through the substratum for porous surfaces and across the surface for non-porous surfaces), buncombe (e.g. bacterial action, oxidation, chemical breakdown due to heat and light, etc.) (Lennard, 2007). The rate of dehydration will depend on certain factors like the temperature, humidity, and exposure to sun, air currents and the surface on which the print was left. Exposure to high humidity can result in diffusion of a water soluble print, causing the print to be lost, and any sensing techniques to be ineffective.Using optical detection techniques will aid in conclusion latent fingerprints. Luminescence will help display a weak friction ridge detail. The best optical detection is achieved by using short-wave ultraviolet (UV) light. This technique is highly effective because the light acts as a contrast between the surface by absorbing the light or reflecting it back showin g the presence of print. leave behind deoxyribonucleic acid Replace Fingerprints in the twenty- first base Century?The use of fingerprints to help solve crimes was first suggested by Dr.Henry Faulds in 1880. Twelve years later, fingerprints that were left in blood at the scene of a doubled murder in genus Argentina were used to convict and identify the killer. However, the first fingerprints accepted in court in the United States didnt happen until 1911.When we are born, we have distinct patterns on the tips of our fingers that will only change under a biological transformation, because once formed in womb, the ridges are permanent and unique to each individual. Biological variation is also known as the natural law of variation and is sometimes stated as genius never repeats (Leo, 2005). There are deuce-ace basic types of fingerprint patterns loops, whorls, and arches. Each of these patterns are arranged to give individuals unique ridges that make up the persons characteristics of fingerprints.It is when these ridges are examined under a microscope side by side with a known artificial lake that a person can be confirmed or eliminated as a suspect. With new technology, fingerprint evidence can be searched through automated fingerprint information systems (AFIS). Fingerprints are used to establish a persons identity in the United States and in every other country in the world. Fingerprints are not just used as evidence in a crime (criminal history), but for employment and security clearances.Deoxyribonucleic red-hot ( deoxyribonucleic acid) was discovered in 1911. It was also discovered that this DNA was the carrier of genetic information. However, it wasnt until 1985 that the structure also established the singularity of each person. One year later, the first use of DNA in a criminal case was used to match a suspect to a double murder in England. The first case of DNA evidence admitted in a United States court didnt happen until 1988. Since then, over t hirty-five states have admitted DNA evidence in one form or another while more than twenty-five states have the population frequency data or statistics to be permissible in court (Leo, 2005).DNA evidence is found at crime scenes as the presence of blood, semen, hair, skin, and saliva. In order to make a comparison a DNA profile must be extracted from the evidence and/or a sample taken from a known individual. A DNA profile is accomplished through a process called electrophoresis.After the profile has been extracted, the results are recorded on an autorad and can be compared to other profiles. There are xiii markers that are used to standardize a national data base called combine DNA Index System (CODIS) in the United States (Leo, 2005). To date, DNA is console appear as we continue to move further into the technological future, and can be used for personal identification, employment, security clearance, or to train criminal histories.Every second of the solar day, millions of fingerprints are being searched via the automated fingerprint systems near the world. Thousands of crimes have been solved because of the fingerprint evidence left behind at the scene of the crime. In 1994, when CODIS began, there have been over 20,000 DNA matches. In Los Angeles County, California, more than d latent prints are matched to criminal wrongdoer on any given day (Leo, 2005). Both methods of identifying an individual play life-and-death roles in solving crime. Although fingerprints are still considered the golden standard for forensic evidence in the courtroom (Leo, 2005), DNA is travel forward in being a very important tool to fleck and solve crime. However, when it comes down to it, both techniques complement each other and provide resilient information to help find criminals. work CitedCoghlan, A. &. (2005). How Far Should Prints be Trusted? natural Scientist, 2517(187), 6-7. Retrieved January 21, 2013, from http//search.ebscohost.com.proxy.devry.edu/login.a spx?direct=true&db=a9h&an=18376323& localise=ehost-live Lennard, C. (2007, December). Fingerprint Detection Current Capabilities. Australian Journal of Forensic Science, 39(2), 55-59. Retrieved January 21, 2013, from http//www.informaworld.com Leo, W. (2005, September/October). give DNA Replace Fingerprints in the twenty-first Century. The Print, 21(5), 1-5. Retrieved January 21, 2013, from http//www.fingerprintidentification.net/sitebuildercontent/sitebuilderfiles/dnavfingerprints.pdf Spraggs, D. (2007, February 01). How to Lift Fingerprints. Retrieved January 20, 2013, from Police Magazine www.policemag.com/ note/patrol/articles/2007/02/how-to-lift-fingerprints.as