3.2 Crime scene investigation - presentation

3.2 Crime scene investigation - presentation - YSCN0017...

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Unformatted text preview: YSCN0017 From Sherlock Holmes to modern forensic science “Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it.” ▬▬▬ Sherlock Holmes ▬▬▬ THE CRIME SCENE THE "Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it." -A. Conan Doyle, The Boscombe Valley Mystery, 1892. Mystery CRIME SCENE ▪ DO NOT CROSS ▪ CRIME SCENE ▪ DO NOT CROSS The objectives of crime scene investigation The is to make use of evidences collected at the crime scene (and all other information) to determine : Has a crime been committed? Has How and when the crime was committed? How Is it the only scene? Is What information can be obtained to identify What the crime perpetrator? Physical Evidence Physical Physical evidence encompasses any and all Physical objects that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator. The evidences are sent to crime laboratories for The analysis. PRINCIPLE OF EXCHANGE PRINCIPLE “…EVERY CONTACT LEAVES ITS TRACES…” Edmond Locard . The Beginning The The investigator must recognize physical The evidence at the crime scene and properly preserve it for laboratory examination. Otherwise, all the sophisticated laboratory Otherwise, instrumentation or technical expertise are useless. Case 3: Kidnapping/Homicide Case The suspect resided at a village house in Yuen Long. The boy may have been detained in the house. The police wanted to determine whether the victim has been held in the house. 3 July 1999 : The boy’s corpse was found in Tsuen Wan Harbour. 30 June 1999 : a boy was kidnapped by a male at Wong Chuk Hang Estate. The Crime Scene The Crime Scene Evidence Crime The police searched the scene in the evening of The 3 July 1999 and found some plastic straps. However, they did not find any evidence to However, associate the victim to the scene. On 4 July 1999, a staff of the Government On Laboratory was requested to examine the scene. The duty SEO located a pink plastic glove in a The litter bin in the kitchen. Crime Scene Evidence Crime Laboratory findings on the glove: Laboratory Victim’s DNA on the outside of the glove. Victim Suspect’s DNA on the inside of the glove. Suspect The findings on the glove provided crucial The evidence to the police in solving the case. The suspect was sentenced to life imprisonment The for the murder of the boy. A mock crime scene investigation “How To Use CSI Techniques To Find Out Who Used Your Coffee Mug”, www.videojug.com CRIME SCENE ▪ DO NOT CROSS ▪ CRIME SCENE ▪ DO NOT CROSS Crime Scene Investigation Crime 1. Secure and Isolate the Crime Scene 2. Record the Scene 3. Conduct a Systematic Search for Evidence 4. Collect and Package Physical Evidence 5. Maintain Chain of Custody 6. Obtain Controls 7. Submit Evidence to the Laboratory 8. Crime-Scene Safety The First Steps The The first officer to arrive at the scene is responsible for The securing the crime scene. First priority should be given to obtaining medical First assistance for individuals in need of it and to arresting the perpetrator. As soon as it is possible, extensive efforts must be As made to exclude all unauthorized personnel from the scene. Once the scene is secured, the preliminary exam must Once begin. Recording of the crime scene becomes a critical piece Recording to the investigation process. The Preliminary Exam The A lead investigator will start the process of evaluating lead the area. First, the boundaries of the scene must be First, determined. Followed by the establishment of the perpetrator’s Followed path of entry and exit. The investigator then proceeds with an initial walkThe through of the scene to gain an overview of the situation and develop a strategy for the systematic examination and documentation of the entire crime scene. This is done before processing the crime scene for This physical evidence. 1. Secure and Isolate the Crime Scene ■ Ropes or barricades along with the strategic positioning of guards are placed to preserve and protect the area by excluding all unauthorized personnel from the scene. Every individual who enters the scene is a potential destroyer of physical evidence. Exception: First priority should be given to obtaining medical assistance for individuals in need of it and to arresting the perpetrator. ■ ■ CRIME SCENE ▪ DO NOT CROSS ▪ CRIME SCENE ▪ DO NOT CROSS 2. Record the Scene ■ ■ ■ Limited time to work a crime site in its untouched state. To record the condition of the crime site and the location of physical evidence for presentation at a trial. Methods of crime-scene recording: 1. photography, 2. sketches, 3. notes. Photography Photography The most important prerequisite for photographing a The crime scene that the crime scene in an unaltered condition. Unless there are injured parties involved, objects must Unless not be moved until they have been photographed from all necessary angles to show their position and location relative to the entire scene. Photography Photography After these overviews are taken, close-ups should be After taken to record the details of the object itself. When the size of an item When is of significance, a ruler or other measuring scale may be inserted near the object and included in the photograph as a point of reference. All objects are marked All with labels. Photography Highly specialized photographic techniques, such as digital imaging, infrared, ultraviolet, X-ray and laser photography may be used to make invisible information visible to the naked eye. Victim's shirt under normal lighting conditions. Victim's shirt illuminated with alternate light source. Photography ■ Three-dimensional panoramic view of the crime scene can be obtained by stitching individual images of the crime scene captured with a digital camera. ■ Modern high resolution Video camera can provide alternative high quality picture of the crime scene. Rough Sketches A draft representation of all essential draft information and measurements at a crime scene. drawn at the crime scene to show all drawn recovered items of physical evidence, as well as other important features of the crime scene. ■ Precisely depict the dimensions and locations of all objects in the scene with help of tape measurement. Number and letter designations are used to describe objects. ■ Finished Sketches ■ Based on the rough sketch, drawn with care and concern for aesthetic appearance. scene, usually drawn to scale. This type is not normally completed at the crime scene. ■ A precise rendering of the crime ■ Computer programs are available for reconstructing crime scenes with computer-aided drafting (CAD) which has a library of predrawn symbols and templates. Notes Notes Note taking must be a constant activity throughout the Note processing of the crime scene. These notes must include a detailed written description of These the scene with the location of items of physical evidence recovered. They must identify: They the time an item of physical evidence was discovered the by whom it was discovered by how and by whom it was packaged and marked how the disposition of the item after it was collected the The note taker has to keep in mind that this written The record may be the only source of information for refreshing one’s memory. Notes Taking ■ Including a detailed written description of the scene with the location of items of physical evidence recovered. ■ To identify the time an item of physical evidence was discovered, by whom, how and by whom it was packaged and marked, and the disposition of the item after it was collected. ■ Tape-recording and videotaping at a scene can be advantageous but finally must be transcribed into a written document. 3. Conduct a Systematic Search for Evidence A crime-scene search will depend on the location and size of the area, the nature of the crime as well as on the actions of the suspect(s) and victim(s) at the scene Case Homicide Weapons Focused types of evidence Burglary Tool marks Hit-and-run Search through outside and undercarriage of the car Blood, tissue, hair, fibers, fabric, Blood, paint and broken glass Hairs, fibers, blood Latent fingerprints 3. Conduct a Systematic Search for Evidence ■ The crime-scene search pattern selected will depend on size and location of the scene and the number of collectors participating in the search. Pan Am Flight 103: 21/12/1988 Pan TIME Europe Case 4: The witness was the seeds of a plant. Beyond The Crime Scene Beyond The search for physical evidence must extend beyond The the crime scene to the autopsy room of a deceased victim. Here, the medical examiner or coroner will carefully Here, examine the victim to establish a cause and manner of death. As a matter of routine, tissues and organs will be As retained for pathological and toxicological examination. At the same time, arrangements must be made between At the examiner and investigator to secure a variety of items that may be obtainable from the body for laboratory examination. Beyond The Crime Scene Beyond • The following are to be collected and sent to the forensic laboratory: Victim’s clothing 1. Fingernail scrapings 2. Head and pubic hairs 3. Blood (for DNA typing purposes) 4. Vaginal, anal, and oral swabs (in sex related 5. crimes) Recovered bullets from the body 6. Hand swabs from shooting victims (for 7. gunshot residue analysis) 4. Collect and Package Physical Evidence Physical evidence must be handled and processed in a way that prevents any change from taking place between the time it is removed from the crime scene and the time it is received by the crime laboratory. Packaging Packaging Each different item or similar items collected at Each different locations must be placed in separate containers. Packaging evidence separately prevents damage through contact and prevents crosscontamination. The well-prepared evidence collector will arrive at a The crime scene with a large assortment of packaging materials and tools ready to encounter any type of situation. Packaging Packaging Forceps and similar tools may have to be used to pick Forceps up small items. Unbreakable plastic pill bottles with pressure lids are Unbreakable excellent containers for hairs, glass, fibers, and various other kinds of small or trace evidence. Alternatively, manila envelopes, screw-cap glass vials, or Alternatively, cardboard pillboxes are adequate containers for most trace evidence encountered at crime sites. Small amounts of trace evidence can also be Small conveniently packaged in a carefully folded paper, using what is known as a “druggist fold.” Packaging Packaging If bloodstained materials are stored in airtight If containers, the accumulation of moisture may encourage the growth of mold, which can destroy the evidential value of blood. In these instances, wrapping paper, manila In envelopes, or paper bags are recommended packaging materials. 5. Maintain Chain of Custody Without a continuous record showing that evidence has been kept safe and secured from the crime scene to the laboratory and ultimately to the courtroom, evidence may be rendered inadmissible in court. ■ ■ ■ ■ Follow standard procedures in recording the location of evidence, marking it for identification, and completing evidence submission forms for laboratory. All items of physical evidence should be carefully packaged and the collector’s initials and the date of collection are inscribed directly on the article or the package bag. If the evidence is turned over to another individual for care or delivery to the laboratory this transfer must be recorded in notes and other appropriate forms. Every individual who has occasion to possess the evidence must maintain a written record of its acquisition and disposition and may be requested to testify in court . Exhibit Seals Exhibit Security Tapes and Signature Security Tape with serial number Voided Serial number 6. Obtain Controls Control (Standard/Reference Sample) is physical evidence of known origin, such as blood or hair from a suspect or victim, that can be compared to crime scene evidence. ■ hit-and-run incident: require the removal of control paint from a suspect vehicle. hair found at the crime scene: compare to control hairs removed from the suspect and victim. bloodstained evidence: compare to whole blood or buccal swab controls obtained all crime-scene participants. ■ ■ 7. Submit Evidence to the Laboratory ■ Evidence is submitted to the laboratory either by mail shipment or by personal delivery subjected to the nature of the evidence, the distance from the laboratory and the urgency of the case. Most laboratories require that an evidence submission form accompany all evidence submitted, which provides detailed descriptions on both the content(s) and the history of the evidence. Care must be exercised in the packaging of evidence in order to prevent breakage or other accidental destruction while it is in transit to the laboratory. ■ ■ 8. Crime-Scene Safety Caution and protection must be used at all times at crime scene because of potential hazards and cross contamination: ■ The presence of blood and semen, sharp objects (e.g., knives, hypodermic syringes, razor blades) and other potentially hazardous matters. Wearing of protective clothes and gloves is essential. The investigators also need to follow a number of guidelines as listed in the table shown in your notes. ■ 8. Crime-Scene Safety Improper Packaging Proper Packaging Sharp end was not protected. All of the seals of the polybag are signed across. The knife was properly secured in a box. Legal Considerations At The Crime Scene ■ The removal of any evidence from a person or from the scene of a crime must be done in conformity with existing legal procedure. Because the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizure, is protected by law Exception for searching without a warrant are: 1. Emergency situation, e.g., someone’s life or health is in danger; 2. Impending loss of evidence, e.g., a fire threatens to destroy the evident; 3. When someone is under lawful arrest, the suspect and any property in his/her immediate control, such as a home or vehicle; 4. Consented search from the parties subjected to search. Violation of such procedure may lead to disqualifying of the evidences by the court. ■ ■ Crime Scene Reconstruction Crime ■ Model can be used to reconstruct the crime scene for presentation in the courtroom. Computer simulation not only can reconstruct the crime scene but showing the sequence of events based on collected evidences. ■ Crime Scene Reconstruction Crime Pan Am Flight 103 at 31000 ft. Crime Scene Reconstruction Crime YSCN0017 From Sherlock Holmes to modern forensic science “Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it.” ▬▬▬ Sherlock Holmes ▬▬▬ ...
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This note was uploaded on 09/06/2010 for the course YSCN YSCN0017 taught by Professor Prof during the Spring '08 term at HKU.

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