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Forensic serology is the application of immunological and biochemical methods to identify the presence of a body fluid or tissue sample encountered in connection with the investigation of a crime and the possible further genetic characterization of the sample with a view to determining likely donors thereof (Ballantyne, 2000). From: Encyclopedia of Forensic and Legal Medicine (Second Edition), 2016
When biological samples of unknown origin are discovered at a crime scene, investigators: A. Should assume pathogens are present and treat the sample as such How is biological evidence collected at a crime scene?Use paper bags, envelopes, boxes and similar materials for all biological evidence. Avoid plastic packaging as an inner or outer package. Avoid the use of pill tins due to possible rust. Ensure that all swabs and evidence are dry. What is biological trace evidence?Trace evidence materials commonly collected from crime scenes typically consist of: u2022 Body Fluids: blood, semen, saliva, sweat and other excretion products.u2022Body Tissues: hair, nails, skin flakes, teeth and bone What is cross contamination of evidence?Cross-contamination – The unwanted transfer of material between two or more sources of physical evidence. For example, improperly collecting biological evidence such as blood could lead to one sample mixing with another sample and contaminating both. Which of the following is a good way for investigators to collect carriers of trace evidence?Use paper bags, envelopes, boxes and similar materials for all biological evidence. Avoid plastic packaging as an inner or outer package. Avoid the use of pill tins due to possible rust. Ensure that all swabs and evidence are dry. Which of the following should be used to collect trace evidence?Investigators should collect possible carriers of trace evidence which may include: vacuum sweepings, clothing, vehicles, amp; fingernail scrapings. How do you gather biological evidence?Summary of Recommendations for the Collection of Biological Evidence for DNA Analysis. Collect as much sample as possible from a single source. Keep biological evidence stain concentrated/do not spread a small stain over a large substrate. Insure that the sample is not inadvertently mixed with other biological samples. How is biological evidence collected and packaged?Use paper bags, envelopes, boxes and similar materials for all biological evidence. Avoid plastic packaging as an inner or outer package. Avoid the use of pill tins due to possible rust. Ensure that all swabs and evidence are dry. What are 5 types of biological evidence?Types of Biological Evidence
How do you collect DNA from a crime scene?In an instance where the crime scene offers a clear source of DNA (blood, urine, saliva, and samples on steering wheels, etc.), the sample can be collected using a swab. After putting on protective gloves, remove the swab from its wrapper, taking precautions to touch only the handle. What is biological evidence evidence?Biological evidence means an individual’s blood, semen, hair, saliva, skin tissue, fingernail scrapings, bone, bodily fluids or other identified biological material. What is defined as trace evidence?To a forensic scientist, trace evidence refers to evidence that is transferred from one person to another person or place. In the forensic world, this concept is known as Locard’s Exchange Principle. What are the three types of biological evidence?Types of Evidence x26gt; Biological Evidence. Blood. Saliva. Semen. What is the most common biological evidence?Sources of DNA Evidence The biological material used to determine a DNA profile include blood, semen, saliva, urine, feces, hair, teeth, bone, tissue and cells. How is evidence contaminated?Webster’s Dictionary defines contamination as; to make impure, corrupt, by contact; pollute, taint. Potential contamination of physical evidence can occur at the crime scene, during the packaging, collection and transportation of the evidence to a secured facility or laboratory, and during evidence analysis and How can cross contamination be avoided evidence?To avoid contamination of evidence that may contain DNA, always take the following precautions: What are some examples of contamination that an investigator can introduce into the crime scene?Contamination can take place in any number of ways including: Police or other first responders interfering with evidence during a tactical investigative response. Suspects interfering with the crime scene to cover up or remove evidence. Victims or witnesses handling evidence. How is trace evidence transferred?These are referred to as trace evidence, and can be transferred when two objects touch or when small particles are disbursed by an action or movement. For example, paint can be transferred from one car to another in a collision or a hair can be left on a sweater in a physical assault. What is the best way to collect trace evidence?When trace evidence is located, it is collected by hand or with a pair of forceps and placed into an appropriately sized packaging, such as a paper bindle. If the location of the trace evidence is significant, record its location by means of a photograph before recovering the item. What are two ways to collect trace evidence?Common collection methods include individual fiber collection using tweezers or vacuuming an area and sorting the materials at the laboratory. Trace evidence can also be gathered by tape lifting, however, this is not ideal due to the destructive nature of adhesives. How do you collect trace evidence found at a crime scene?Place small glass fragments in paper bindles, then in coin envelopes, pill boxes, or film cans which can be marked and completely sealed. Place large glass fragments in boxes. Separate individual pieces with cotton or tissue to prevent breakage and damaged edges during shipment. Which one of the following are possible carrier of trace evidence?Investigators should collect possible carriers of trace evidence which may include: Vacuum sweepings, clothing, fingernail scrapings. What should be used to collect trace evidence?When trace evidence is located, it is collected by hand or with a pair of forceps and placed into an appropriately sized packaging, such as a paper bindle. If the location of the trace evidence is significant, record its location by means of a photograph before recovering the item. What are 4 types of trace evidence?Common collection methods include individual fiber collection using tweezers or vacuuming an area and sorting the materials at the laboratory. Trace evidence can also be gathered by tape lifting, however, this is not ideal due to the destructive nature of adhesives. How do you collect biological evidence?May consist of blood, skin, hair, semen, saliva, and urine. 19-May-2021 |
When biological samples of unknown origin are discovered at a crime scene what should Investigators do?
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