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Methods of forensic investigation
Methods of forensic investigation
Methods of forensic investigation
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Glitter as Forensic Evidence
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. In order for evidence to be used in court, it must be collected and tested by valid methods. The collection of evidence must be completed carefully and properly to prevent cross-contaminating or destroying the evidence. Before evidence can be collected at a crime scene, the area must be secured to ensure everyone stays safe and that the evidence is not destroyed. After the scene is secured by all proper measures, the collection process can begin. The first items to be collected are those that are transient, fragile or perishable. Hair, fibers and small shards of glass are all
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Fingerprints are collected from the evidence, and ran through a database such as IAFIS. DNA evidence that is extracted from hair, bodily fluids and skin cells are also ran through databases that help identify the suspects. Firearms, bullets and cartridges are analyzed and can be used to trace a weapon back to its owner. All of the information gathered from collected evidence is pooled together to create a solid base for use in the conviction of suspects in a crime. Most items that are considered to be forensic evidence are items found at a majority of crime scenes. These things are collected at every scene they are found at because they are known to be useful pieces of
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.
If there was no weapon found at the scene and there are other evidence clues that lead to a suspect, and if the suspect had a firearm the forensics team would get a warrant to retrieve the weapon so it could be tested. When the weapon is being tested, it will allow the the bullet have individual marks that will be compared to the ones found at the scene. All of these comparisons are done under a microscope since technology has improved and it is easier to make matches. According to Young & Ortmeier (2011) “class characteristics include weight of the projectile, direction of twist of the riffling, degree of twist of riffling, number of lands and groves, and width of lands and groves.” Even though guns from the same manufacture will never have the same riffling, lands or grove. When evaluating two cartridge casings the examiner will be looking for manufacture, the size of the firing pin as well as the location. The FBI has made a integrated ballistic identification system (IBIS) it's a database that helps crime labs with comparisons where it proves one gun being used in many crimes. In addition, gunshot residue is helpful solving crimes because gunshot residue can be chemically tested. If an individual has gunshot residue it doesn't prove he or she shot the victims, it just means that they were along the premises while the gun was fired. Another
Evidence essentially comes in two forms: verbal or physical. For instance, verbal evidence could be spoken evidence acquired from a wiretap. Physical evidence could include DNA, blood, or bodily samples. Another reliable origin evidence is digital documentation. “As technology has become more portable and powerful, greater amounts of information are created, stored, and accessed” (GEDJ). Over the past few decades, technology has advanced to extreme levels! The most common technology used to find digital evidence are cell phones, computers, tablets, external storage devices, GPS locators, and various other devices (GEDJ). Text messages, social media posts, pictures, etc. are becoming more common data in investigations of the modern era. “Digital evidence can come from both suspects and victims, as all involved parties may have their own personal devices that are relevant to the investigation” (GEDJ). If they are available, computers, phones, social media and much more are very useful sources of gathering data for a criminal case. For instance, both the suspect and the victim may have text messages on their cell phones that could add to the search. “In some criminal cases, digital evidence can be useful if the suspect had associated with it. In some cases it can lead you in the wrong direction or to the wrong people. Or it could simply be useless if the suspect didn 't use anything
Crime scenes are known to have many clues left behind. The obvious would be a the body or bodies, clothing, and sometimes even the murder weapon. While these are great way to solve a case there's another kind of evidence; trace evidence. Trace evidence are small pieces of evidence that are laying around a crime scene. There are many types of trace evidence some of them include metal filings, plastic fragments, gunshot residue, glass fragments, feathers, food stains, building materials, lubricants, fingernail scrapings, pollens and spores, cosmetics, chemicals, paper fibers and sawdust, human and animal hairs, plant and vegetable fibers, blood and other body fluids, asphalt or tar, vegetable fats and oils, dusts and other airborne particles, insulation, textile fibers, soot, soils and mineral grains, and explosive residues. Although these are the most common found elements, they are not the only ones. The Trace Evidence Unit is known to examine the largest variety of evidence types and used the biggest range of analytical methods of any unit. materials are compared with standards or knowns samples to determine whether or not they share any common characteristics. In this paper I will discuss the different kinds of trace evidence and how crime scene investigaros use it to solve cases and convict 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
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...
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.
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).
Crime investigators have the job to solve crime and find the suspect responsible. Sometimes the offense is very difficult to solve, but with the right pieces of evidence and tools, the investigation can be answered a little more easily. The use of fingerprints is a main tool used at crime scenes. Investigators find these at the actual crime scene and analyze them at the lab to determine whom the prints belong to. Each person has an individual print which is why this is a very useful piece of evidence. Sir Francis Galton found that the prints could be categorized into different types as well as different groups. The research of fingerprints from decades before has shaped the way detectives identify suspects and victims.
In conclusion, trace evidence has been and still is a major factor when solving crimes. History of trace evidence has shown the appreciation of advanced technology and just how much easier it is to find a true criminal. Trace evidence is one of the major studies that help prove a suspect’s wrongness with hair follicles, saliva, bodily fluids, fabrics, and much more. Today, trace evidence is still truly helping many investigators find the murderer of most crimes, even though it sometimes takes thirty- two years to solve.
The amount of evidence can either help win or lose a case. Every crime scene has evidence available for officers to collect. It is important for them to know what the standard protocol is for collecting evidence and how to properly collect it without contamination.
As far back as 1832, James Marsh was the first to use forensics at trial to give evidence as a chemist in 1832. Since that time forensic science and evidence has come a long way in various ways and technology to help in determine if the suspect is guilt or not, through such things as DNA testing, blood, and fingerprints. The first forensic police crime lab was created in 1910. The contributions of Dr. Edmond Locard, a French scientist and criminologist, proposed that “everything leaves a trace”. This principle is still valid today as it was so many years ago. No matter how small, the specialized trained technicians and investigators can take these methods and go to a crime scene to get evidence. “Forensic science is the application of sciences such as physics, chemistry, biology, computer science and engineering to matters of law.” (Office of Justice, 2017) These different sciences can help achieve and assist in solving a case. Forensic science has also the ability to prove that a crime was committed, it can find the elements of the crime, it can help place the suspect at the scene and whether the suspect had any contact with the victim. However, in the last several years the techniques and with the use of technology the evidence that forensic science uncovers can also exonerate an innocent individual who has been falsely accused of the
Physical evidence is real evidence that is collected, packaged and analyzed. Examples are; hair fibres, blood samples and skin flakes. Physical evidence is either identified or individualized. (links to one person - finger prints or DNA) At a typical crime scene the FAO (First Attending Officer) would be called. They would check the scene is safe to enter (in case... ...
“The word ‘forensics’ means “connected with the courtroom”; so forensic science is, therefore, concerned with gathering hard evidence that can be presented in a trial” (Innes 9). Forensic science is a science that is applied specifically to legal matters, whether criminal or civil. “Few areas in the realm of science are as widespread and important as forensic science” (Hunter 12). Forensics is the one science that is most commonly used in everyday life. It is also a branch of science that incorporates other branches of science such as biology, chemistry, and etc. Since it is used almost every day “No one can dispute the importance of the contributions to society made by forensic science; the ability to solve crime is undeniably important” (Hunter 13). Forensic science has given criminal investigation a new edge. “Advances in science have opened the door for more effective evidence discovery, howev...
The process of gathering evidence largely depends on the role of discretion by the police. Once police have decided to pursue a reported crime, they then begin the process of gathering evidence. To ensure that the process of gathering evidence is lawful, the police must follow the procedure outlined in the Evidence Act 1995 (NSW), which describes the manner in which evidence can be collected. This act imposes certain limits on the way police can gather evidence and the types of evidence that can be used. The Act is able to protect the rights of citizens by making it a requirement for the police to gain necessary legal documentation, such as search warrants, in order to obtain some types of evidence and thus, protects the rights of ordinary systems. In more recent times, the use of technology has come to play a major role in the gathering of evidence and with this comes complications in the law. New technologies in relation to the criminal investigation process are mainly in reference to DNA evidence, genetic material that can place a suspect at the scene of a crime. The introduction of DNA evidence into the criminal investigation process has been extremely effective in achieving justice, as it is able to secure convictions. Initially, there were some setbacks to the use of DNA evidence