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Forensic Science
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Copyright and Terms of Service Copyright © Texas Education Agency, 2011. These materials are copyrighted © and trademarked ™ as the property of the Texas Education Agency (TEA) and may not be reproduced without the express written permission of TEA, except under the following conditions: 1) Texas public school districts, charter schools, and Education Service Centers may reproduce and use copies of the Materials and Related Materials for the districts’ and schools’ educational use without obtaining permission from TEA. 2) Residents of the state of Texas may reproduce and use copies of the Materials and Related Materials for individual personal use only, without obtaining written permission of TEA. 3) Any portion reproduced must be reproduced in its entirety and remain unedited, unaltered and unchanged in any way. 4) No monetary charge can be made for the reproduced materials or any document containing them; however, a reasonable charge to cover only the cost of reproduction and distribution may be charged. Private entities or persons located in Texas that are not Texas public school districts, Texas Education Service Centers, or Texas charter schools or any entity, whether public or private, educational or non- educational, located outside the state of Texas MUST obtain written approval from TEA and will be required to enter into a license agreement that may involve the payment of a licensing fee or a royalty. Contact TEA Copyrights with any questions you may have.TEA Copyrights 2
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Isolate and secure the scene Document the scene Search for evidence Collect and package the evidence while maintaining the chain of custody Submit the evidence for analysis 3
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. A – Assess the crime scene and assist the injured D – Detain the witness(es) A – Arrest the perpetrator P – Protect the crime scene T – Take notes 4
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. 1) Look for signs of life 2) Cordon off the scene (only allow authorized personnel in) 3) Bodies should be certified as “dead” by a medical examiner (ME) before being moved 5
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. A walkthrough is performed by the crime scene investigator, the first officer, and sometimes the lead detective Record initial observations of who, what, where, when, and how Make a plan of action 6
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Record the crime scene and potential evidence with Notes Photography Sketches Videography 7
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Record the following while at the crime scene (details are the key): Date Time Description of the location, weather, and environmental conditions Description of the crime Location of the evidence relative to other key points Names of all people involved Any other relevant information 8
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Nothing should be moved until photographed Take photos of the scene and the surroundings Photograph entrances and exits Take wide and close-up photos Use various angles for each piece of evidence Use a ruler to show size 9
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Narrate the video Be objective Record from different perspectives 10
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Draw a rough sketch at the scene (reconstruct it better later) Include Date, time, and location Scale Recovered items Important features Accurate distance measurements of objects (from two fixed points) A legend for description of items A compass designating north Names of investigators, victims, and suspects 11
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. 12 Include 2 lines to show distance from evidence to a reference point, such as the wall
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. When searching a crime scene, wear the following, if available, to minimize contamination Disposable gloves Masks Coveralls with a hood Slippers 13
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Depend on the size and the location of the crime scene and the number of investigators available Stick to one pattern and one supervisor Better to collect everything and not need it than fail to collect something and need it later 14
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Spiral Spiral – may move inward or outward; best used where there are no physical barriers Grid Grid – basically a double-line search; effective, but time-consuming Line (Strip) Line (Strip) – best in large, outdoor scenes Zone (Quadrant) Zone (Quadrant) – most effective in houses or buildings; teams are assigned small zones for searching 15
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. SpiralGrid Strip or LineQuadrant or Zone 16
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Physical evidence must be packaged and collected before time and weather can alter it Physical evidence – any object that can establish that a crime has been committed or links a crime and the victim or suspect The Golden Hour – the window of opportunity to collect time-sensitive information or evidence 17
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Each item must be placed in a separate container, and sealed and labeled The most fragile evidence is collected and packaged first Different types of evidence require specific or special collection and packaging techniques The body is the property of the coroner or medical examiner; collection of evidence on the body is done by that department 18
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Containers such as vials, envelopes, plastic bags, paper bags, canisters, and cardboard boxes are good packaging devices Most items should be placed in a primary container and then in a secondary container Trace evidence may be placed on a piece of paper which is then folded in a “druggist fold” and placed in a secondary container 19
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Containers should be sealed with tamper proof tape, and dated and initialed Each package should contain Description of contents Date, time, and location Agency and collector’s name Case number Victim’s name(s) Never package two items from two different sources or locations 20
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. There must be a written record of all people who have had possession of an item of evidence, beginning at the time of collection Every person who handled or examined the evidence must be accounted for Chain of Custody should include Date and time of transfer Location of transfer To/From names Purpose of the transfer 21
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. Crime Scene Investigators can submit evidence for analysis to several national databases based on the type of evidence Examples include AFIS Automated Fingerprint Identification System (AFIS) IAFIS Integrated Automated Fingerprint Identification System (IAFIS) CODIS Combined DNA Index System (CODIS) IBIS Integrated Ballistics Identification System (IBIS) PDQ International Forensic Automotive Paint Data Query (PDQ) 22
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Copyright © Texas Education Agency 2011. All rights reserved. Images and other multimedia content used with permission. 0135158494, Saferstein, Richard. Forensic Science: An Introduction. New Jersey: Pearson Prentice Hall, 2008. 0757518257, Ball-Deslich, Barbara and John Funkhouser. Forensic Science for High School. 2 nd Edition. Kenall/Hunt, 2009. 23
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