Crime-Scene Investigation and Evidence Collection PDF

3 is to recognize, document, and collect evidence at the scene of a crime. Solving the crime will then depend on piecing together the evidence to form a picture of what happened at the crime scene When two people come into contact blood/ hair/ skin ce...

3 is to recognize, document, and collect evidence at the scene of a crime. Solving the crime will then depend on piecing together the evidence to form a picture of what happened at the crime scene When two people come into contact blood/ hair/ skin cells/ cloths with each other, a physical transfer makeup/ Pet hair on clothes or rugs/ Soil occurs from one person to another tracked on shoes/ Fingerprints on a glass/ A used facial tissue any number of different types of material can be transferred from one person to another The first person to note this condition was Dr. Edmond Locard, director of the world’s first forensic laboratory in Lyon, France. Trace evidence can be found on both persons and/or objects  States that: the intensity, duration, and nature of the materials in contact determine the extent of the transfer That’s mean: More transfer would be noted if two individuals engaged in a fistfight than if a person simply brushed past another person Includes firsthand observations such as eyewitness accounts or police video cameras For example, witnesses states that they saw a suspect pointing a gun at a victim during a fighting Is indirect evidence that can be used to imply a fact but that it self does not directly prove the crime. So, circumstantial evidence found at a crime scene may provide a link between a crime scene and a suspect For example, finding a suspect’s gun at the site of a shooting is circumstantial evidence of the suspect’s presence there includes impressions body fluids, hair fingerprints plant and animal parts footprints, shoe prints, tire impressions, tool marks, All natural fibers fibers, weapons, bullets can be either physical or biological in nature Trace evidence is a type of circumstantial evidence Most physical evidence, with the exception of fingerprints, reduces the number of suspects to a specific, smaller group of persons. Biological evidence may make the group of suspects very small, or reduce it to a possible person, which is more convincing in court.  narrows an identity to a group of persons or things. For example: Knowing the blood type of a sample from a crime scene tells us that one of many persons may have been there and allows to exclude anyone with a different blood type narrows an identity to a single person or thing. For example: fingerprint which typically has a unique combination of characteristics that it could only belong to one person or thing.  are usually the first to arrive at a crime scene 1 look for clues by interviewing witnesses & talking to the crime-scene investigators about the evidence may be present & who determine if a search warrant 2 is necessary for the crime-scene investigators may be present to document & collect the evidence 3 include recorders, sketch artists, photographers , and evidence collectors 4 may be necessary to determine the cause of a death when a homicide has occurred 5 such as biologists, forensic scientists, and forensic psychologists may be consulted if the evidence requires their expertise  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Scanning the scene Separating the witnesses Securing the scene scene investigation The main points of crime-  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Scanning the scene Separating the witnesses Securing the scene Forensic Sciences Special Areas of the Securing the scene  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Scanning the scene Separating the witnesses      Securing the scene Forensic Sciences Special Areas of the Securing the scene  Separating the witnesses   Special Areas of the  Forensic Sciences Scanning the scene Seeing the scene Securing the scene Sketching the scene Separating the collecting evidence witnesses Searching for Securing and evidence  When did the crime occur?  Who called in the crime?  Who is the victim?  Can the perpetrator be identified?  What did you see happen?  Where were you when you observed the crime scene?  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Scanning the scene Forensic Sciences Special Areas of the Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Searching for evidence Sketching the scene Seeing the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Searching for evidence Sketching the scene Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Searching for evidence Sketching the scene ) Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Questioned Documents Searching for evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Securing and collecting evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Securing and collecting evidence Securing and collecting evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Packaging Evidence Securing and collecting evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  Packaging Evidence Securing and collecting evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene    Packaging Evidence Securing and collecting evidence Searching for evidence Sketching the scene Forensic Sciences Special Areas of the Seeing the scene Scanning the scene Separating the witnesses Securing the scene  In securing the evidence, maintaining the chain of 1 custody is essential. The individual who finds evidence marks it for identification and bags it in a plastic or paper container, which is labeled 2 with the pertinent information. sealed, and the collector’s signature is written across the sealed edge. The container is given to the next person responsible for its 3 care. Any one who deal with it must sign to receive, opens it from another location than the sealed edge, repackages with its original packaging, reseals, and signs. 4 This process ensures that the evidence has been responsibly handled as it was passed from the crime scene to a courtroom.  Following a crime-scene investigation, the criminal/forensic laboratory work begins. The laboratory results are sent to the Evidence analysis can link a suspect lead detective, who determine how it with a scene or a victim, confirm the fits into the overall crime scenario and identity of a victim or suspect, compared with the witnesses’ confirm witness accounts, or even statements to determine the reliability acquit the innocent. of their accounts. In most cases, Direct evidence is more The evidence does not lie, but convincing than circumstantial investigators must consider all evidence. possible interpretations of the evidence. Both of them Crime-scene reconstruction. The perpetrator stages a fire A victim is murdered, and the A burglary is staged to to cover some other crime perpetrator stages the scene collect money such as murder or burglary to look like a suicide. The death may be caused by alcohol or drug overdose.  the following points should be considered Initially treat all death Could the wounds be Evaluate the behavior investigations as homicides. easily self-inflicted? (mood and actions) of the victim before the event. Do the type(s) of wounds Establish a profile of the victim found on the victim match through interviews with friends and the weapon employed? family.  the following points should be considered Evaluate the behavior (mood Reconstruct the event and actions) of any suspects before the event Match the informations Do all forensic examinations to with the evidential facts determine the facts of the case firsthand = ‫بشكل مباشر‬ Circumstantial =‫غير مباشر‬ 1 Prosecutors = ‫النائب العام‬/‫وكيل‬ search warrant =‫مذكره التفتيش‬ Responder = ‫المستجيب‬ restricting =‫منع‬/‫تقييد‬ 2 unauthorized = ‫غير مصرح‬ immovable = ‫ثابت‬ vicinity = ‫منطقه مجاوره‬ spiral = ‫حلزونى‬ grid = 3‫شبكه‬ linear = ‫خطى‬ quadrant = ‫رباعى‬ extraneous material = ‫شيئ غير مرغوب به‬ airtight = ‫محكم الغلق‬ mold contamination = ‫التلوث بالعفن‬ 1 paper bindle = ‫غالف ورقى‬ chain of custody = ‫سلسله العنايه‬ exclusion = ‫االستبعاد‬ pertinent = ‫ذات صله‬ fits into 2 = ‫يالئم‬ reliability =‫مصداقيه‬ innocent = ‫برئ‬ acquit = ‫تبرأه‬ burglary = ‫السطو‬ wounds = ‫الجروح‬ 3 self-inflicted = ‫ذاتيه‬  The goal of a crime-scene investigation (recognize, document, and collect evidence) Locard’s exchange principle (1st and 2nd part) 1 Types of evidence (direct and Circumstantial) or (class and Individual) Types of Circumstantial evidence (Physical and biological) The crime-scene investigation team Securing the scene ( First Responder police officer/s, 1st and 2nd priority ) 2 Separating the witnesses Scanning the scene (primary and secondary crime scene) Seeing the scene (Photos ) Sketching the scene (accurate sketch ) 3 for evidence (Single or group of investigators) Searching Securing and collecting evidence (properly packaged, sealed, and labeled) & (dry , Liquids, arson, wet ) & (evidence log and chain of custody ) Analyze the evidence (criminal/forensic laboratory)