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Criminal investigations, forensics and evidence
Criminalistics Forensics
Criminalistics Forensics
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Recommended: Criminal investigations, forensics and evidence
5) In the virtual museum game; 5 of the different forensic techniques used were:
Tool mark analysis- This is where the forensic investigators will photograph or sketch (when the whole area can’t go to the lab) impressions made by tools used in the crime. At the lab, they will compare tools and marked objects to identify specific tools. 3 types of tool mark impressions are: compressions; pressed into soft materials, sliding; tool scrapes across surfaces, and cutting; a combination of both compression and sliding.
Imagery/computer composite- When a witness is present; a forensic sketch artist will get as much information as possible to do a composite drawing of a suspect; either manually or use a computer. Sometimes; they will use both, using
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One of the important pieces of evidence was the absence of all but a trace of gunshot residue. It was successfully argued that the residue could have resulted from his handling of his wife's body or touching the interior of the car in which she was found. This technique is not always reliable in solving a case, for example; the Tyree Wright murder case on June 24th, 1998. Police arrested Tyrone Jones, who seemed to fit the description, and he was swabbed for gunshot residue on his hands after he was arrested. He was swabbed after being in the police car, interview room, and in handcuffs (all of which have a high probability of containing gunshot residue on its own). After analysis he was charged for murder and brought to court. Jones was sentenced to life in prison and is currently trying to get an …show more content…
Next the restriction enzymes are used to cut the DNA into smaller pieces. Restriction enzymes work by cutting the DNA at a specific sequence and results in many fragments of different lengths. These fragments are called restriction fragments length polymorphisms (RFLP’s). These RFLPs are then put into an agarose gel. Using gel electrophoresis, the fragments are sorted according to size. When the current of the electric field is turned on, the negative RFLPs will start to move across the gel towards the positive end. The smaller fragments move farther across the gel than the larger ones. The gel is then covered by a piece of nylon and thin paper towels, which are used to absorb moisture from the gel. The DNA fragments get gently transferred from the gel to the surface of the nylon. This process is called blotting. Radioactive probes get washed over the nylon surface. These probes will join to any DNA fragments that share the same composition. The final step to making a genetic fingerprint is to place a photographic film on top of the nylon surface. The probes leave marks on the film wherever they attached to the RFLPs. Dark bands will then show up when the film is developed, which marks the length of the RFLPs. Then scientists are able to compare the DNA from the crime scene and the DNA from a
Other evidence located within the grave consisted of a generic watch, two cigarette butts, a button, a washer and a shell casing. All of these could be analysed for finger prints and DNA. The cigarette butts would also show a serial number indicating the brand (shown in Figure 3), which can be useful if it is found a victim or offender smokes a particular type of cigarette.
From a trial strategy point of view, you always start with the piece(s) of evidence you believe are most damaging to the client's case and work backwards looking for an exploitable flaw in the search and seizure procedure that would make that or those item(s) inadmissible. The further back in the series of events you can argue a fatal flaw, the more likely that the evidence and any additional materials which flowed from that particular item of evidence will be excluded. This is the practical analysis of all the times we see or hear of law enforcement arguing that there was some technical item which drew their attention and suspicion and justifies their hunch that criminal activity is afoot.
When it comes to identical twins we have come to learn that twin identical or not will not have the same fingerprint. Fingerprints are unique and are made to identify a person. So even when you clone humans or other primates I believe that the Friction ridge pattern will be similar but not exactly the same. I believe that in the process of the cloning process something will cause the fingerprints to come out different. Because cloning is dangerous there has yet to be a human cloning, but there have been cloning of monkeys and according to the data even though the monkey was cloned the fingerprint still isn’t the same.
At the initial stage of the investigation all the visible evidence is to be observed from the latent impression perspective. At this stage only the physical evidence is taken into account. The objects can be divided into porous and non-porous surfaces from the imprint ability preservation perspective. It is advisable to send all the available evidence to the laboratory expertise, though the non-porous substances...
CSIs must photograph/sketch crime scenes, take measurements, make observations, testify against criminals in court, and collect, pack, label, document, and analyze evidence (Career Cruising). All of these tasks CSIs must complete, require them to handle a variety of tools including: cameras, tripods, flashlights, notepads, utensils to collect physical evidence, measuring tapes, rulers, microscopes, fingerprinting kits, and even guns in some cases (Career Cruising). CSI agents collect to different types of evidence, when they investigate a crime (Byrd). The first type of evidence is testimonial evidence, which is the answers CSIs questioning suspects and witnesses are given (Byrd). Physical evidence, which is the other type of evidence, is any type of three-dimensional evidence collected at a crime scene (Byrd). Although different CSI teams from different areas of the world can consist of multiple branches, including: detectives, technicians, medical examiners, scientists, and lab analysts, they still use forensics, which is science and technology, to investigate crimes (Zullo). There is always crime, but when there are no current cases; CSIs go back to old/previous cases (McFadden).
As you can see there is no perfect crime. The littlest piece of hair or paint or anything left behind can be found. Suspects often miss these tiny peieces of evidence and while they looked over it, it is still lurking at the crim scene. It is guarenteed that a Crime Scene Investigator will find this evidence no matter how small and use it to find, prosecute, and convict a criminal.
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
In order to understand how to compile evidence for criminal cases, we must understand the most effective types of evidence. This topic is interesting because there are ample amounts of cases where defendants have gotten off because of the lack of forensic evidence. If we believe forensic evidence is so important and it affects our decisions, then maybe we need to be educated on the reality of forensic evidence. If we can be educated, then we may have a more successful justice system. If we have a more successful justice system than the public could gain more confidence that justice will be served. In order to do this, we must find what type of evidence is most effective, this can be done by examining different types of evidence.
All individuals, except identical twins, have unique DNA. DNA fingerprinting is an unambiguous identification method that takes advantage of the difference in the DNA sequence. This process of DNA fingerprinting starts with the isolation of the DNA from the identified sample, such as blood, saliva, semen or other body tissues. In instances where the available sample is small for the process of fingerprinting, then the sample is augmented through a process called polymerase chain reaction (PCR). PCR is the process of DNA replication that does not use living cells and, therefore, the process is appropriate in fingerprinting old samples. The focus of this process is on the short tandem repeats (STR) that have short units of DNA that are repeated several times in a row. After the DNA is isolated and amplified it is treated with restriction enzymes. This process cuts the DNA strands at definite sequences called restriction fragment length polymorphisms (RFLPs). Since everybody’s DNA is different the resulting RFLPs will be of different sizes. These fragments are observed in gel electrophoresis; a process that separates DNA based on the size of fragments. RFLP analysis is based on the fact that since everyone’s genetic sequence or the variable number of tandem repeats is different this result in the different sizes of RFLPs. Gel electrophoresis involve the separation of the fragments of DNA as they migrate through an agarose gel when an electric current is applied to the gel. The DNA that has separated is then drawn out of the gel with a nylon membrane which is treated to break the hydrogen bonds holding the DNA strands together. The separated strands of the DNA is then cross-linked to the nylon membrane a...
The article, “Trial Lawyers Cater to Jurors’ Demands for Visual Evidence,” written by Sylvia Hsieh stresses the importance of visual evidence. Hsieh writes
Forensic Art is a sometimes misunderstood and ignored resource for the law enforcement community. Starting with what Forensic Art is defined as, most commonly, it is perceived as any art that can or is used in law enforcement or legal proceedings. This field has several recognized skill sets most prevalent of which are demonstrative evidence, crime scene/composite sketches, image modification/ identification, and postmortem or facial reconstruction. Having a history stretching back to the 1800s forensic art has grown and improved over the course of the following years. First giving a brief history on where forensic art started and then following with some of the benefits each skill set of forensic art provides to the law enforcement community. I will try to show the progression of forensic art and how it can be used by modern law enforcement.
Forensic evidence is “evidence obtained by scientific methods …. and used in court.” Most evidence collected can be classified as either transient evidence or tangible evidence. Common types of transient evidence includes hair, fibers and glass, fingerprints, shoe prints, bare foot impressions and tire impressions, bodily fluids and skin cells, as well as gunshot residue. Some forms of tangible evidence would be firearms, fired and unfired bullets and cartridges, tool marks, drugs and drug paraphernalia, physical documents such as checks and receipts, and computers, cell phones and other devices.
A forensic interview is a structured conversation with a child or minor with the intention of eliciting detailed information about a possible event (s) that the child many have experienced or witnessed. Concurrently, for Van Heerden (1977: 8) forensics refer to the computerized activities or scientific knowledge employed by law enforcement agents to serve justice. In the study, forensic investigation is used to refer to any computer-related activities or methods used by police, investigators, prosecutors and all other law enforcement agents to gather facts, track down criminals, arrest or detain them, gather information, preserve information and finally present it in the court of law.
Forensic Science, recognized as Forensics, is the solicitation of science to law to understand evidences for crime investigation. Forensic scientists are investigators that collect evidences at the crime scene and analyse it uses technology to reveal scientific evidence in a range of fields. Physical evidence are included things that can be seen, whether with the naked eye or through the use of magnification or other analytical tools. Some of this evidence is categorized as impression evidence2.In this report I’ll determine the areas of forensic science that are relevant to particular investigation and setting out in what method the forensic science procedures I have recognized that would be useful for the particular crime scene.
What is DNA? DNA is deoxriybonucleic acid which is a molecule that is in a double-helix structure described by James Watson and Francis Crick in 1953. DNA contains our genetic code which is composed of triphosphate molecules, which are also known as the ‘building blocks’ of DNA. There are four bases included in the DNA molecule they are called the four nitrogenous bases. The bases are Thymine, adenine, guanine (purines), thymine and cytosine (pyrimidines) (http://forensicsciencecentral.co.uk/dna.shtml). This shows that DNA isn’t so easy to understand, there is certain bases to make up the DNA molecule. This is important because it helps compose the pieces to DNA and helps find traces to the victim. “The more useful sources include blood, semen, vaginal fluid, nasal secretions and hair with roots” (http://forensicsciencecentral.co.uk/dna.shtml). This quote is important because it singles out the most occurrence of DNA. In order for DNA testing to take place scientists will have t...