Forensic Science - 02 Crime scene investigation & evidence collection


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A closer look at crime scene investigation and evidence collection for Year 9 students at Saint Ignatius College Drysdale.

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  • Securing the scene. = first responding police officer/Safety & preservation of evidenceSeparating the witnesses. = responding police officer/To avoid collusion (deliberate or otherwise)Scanning the scene. = forensic examiners/to prioritize investigation (primary v secondary crime scene)Seeing the scene. = forensic examiners/to enable crime scene examiner to see the scene later incl different views/angles/points of referenceSketching the scene. = forensic examiner/noting the body & other evidence in relation to two immovable landmarksSearching for evidence. = forensic examiners, police officers, etc/to discover evidenceSecuring and collecting evidence. = forensic examiner, police officer/ensure evidence is protected from being lost/damaged/tampered with incl Chain of custody
  • Forensic Science - 02 Crime scene investigation & evidence collection

    1. 1. DRYSDALE CSI Crime-scene investigation & evidence collection. Ian Anderson Saint Ignatius College Geelong
    3. 3. TRACE EVIDENCE. Evidence that occurs when different objects contact one another. Examples include:  Pet hair on your clothes or carpet.  Hair on your brush.  Fingerprints on a glass.  Soil tracked into your house from your shoes.  A drop of blood on your clothes.  A fibre from clothing.  A used tissue. Locard’s Exchange principle.  Whenever two people come in contact with each other a physical transfer occurs.  The intensity, duration & nature of the materials in contact determine the extent of the transfer.
    4. 4. TYPES OF EVIDENCE. Classified into two types  Direct evidence  Circumstantial evidence.
    5. 5. TYPES OF EVIDENCE. Direct evidence.  Proves an alleged fact.  First-hand observations e.g. eyewitness accounts, police dashboard video cameras, cctv cameras, etc. limit/story-fn8m0sve-1226264497500
    6. 6. TYPES OF EVIDENCE. Circumstantial evidence.  Indirect evidence that can be used to imply a fact.  Does not directly prove that fact!  Can be either physical or biological in nature. e.g. Physical evidence = fingerprints, footprints, tyre impressions, fibres, weapons, bullets, etc. Biological evidence = body fluids, hair, plant parts, natural fibres.
    7. 7. TYPES OF EVIDENCE. What is trace evidence?  Direct or circumstantial evidence? = circumstantial evidence . Class evidence v Individual evidence  ABO blood group = ?  Fingerprints = ? nt3/index.php
    9. 9. THE CRIME-SCENE INVESTIGATION TEAM. Who is involved in a crime-scene investigation?  Police officers  Crime-scene investigators  Medical examiners  Detectives  Specialists. misused-by-cops/story-e6frg14u-1226224499500
    10. 10. THE SEVEN S’S OF CRIME-SCENE INVESTIGATION. 1. Securing the scene. 2. Separating the witnesses. 3. Scanning the scene. 4. Seeing the scene. 5. Sketching the scene. 6. Searching for evidence. 7. Securing and collecting evidence. Why? And Who is responsible?
    11. 11. CHAIN OF CUSTODY. Ensures that the evidence has been responsibly handled as it was passed from the crime scene to courtroom.
    12. 12. CASE STUDY 1 – LILLIAN OETTING (1960) Three Chicago socialites were murdered in Starved Rock State Park, Illinois. All three women had fractured skulls. Their bodies, bound with twine, were found in a cave. Near the bodies of the women, a bloodied tree limb was found and considered to be the murder weapon. Because all three women had been staying at a nearby lodge, the staff of the lodge was questioned. Chester Weger, a 21-year-old dishwasher at the lodge, was asked about a blood stain on his coat. He said it was animal blood. He agreed to take a lie detector test and passed it. He was requestioned and took a second lie detector test and passed it as well. The blood was examined by the state crime lab and found to be animal blood as Weger had indicated at questioning. The case reached a dead end. Source: starved-rock-murders.html
    13. 13. Investigators decided to revisit the evidence. The rope used to bind the women was examined more carefully. It was found to be 20-stranded twine sold only at Starved Rock State Park. Identical twine was found in an area accessible to Weger. He again became a prime suspect. The blood on his coat was reexamined by the FBI Crime Lab and found to be human and compatible with the blood of one of the victims. Weger submitted to another lie detector test and failed it. Weger was found guilty for the murder of one of the women, Lillian Oetting, and has spent more than 45 years in prison. He recently petitioned the Governor of Illinois for clemency, saying he was beaten and tortured into making the confession. He still maintains his innocence. CASE STUDY 1 – LILLIAN OETTING (1960) Source: starved-rock-murders.html
    14. 14. CASE STUDY 2 – THE ATLANTA CHILD MURDERS (1979–1981). Wayne Williams is thought to be one of the worst serial killers of adolescents in U.S. history. His victims were killed and thrown into the Chattahoochee River in Georgia. Williams was questioned, because he was seen near where a body had washed ashore. Two kinds of fiber were found on the victims. The first kind was an unusual yellow-green nylon fiber used in floor carpeting. Through the efforts of the FBI and DuPont Chemical Company, the carpet manufacturer was identified. The carpet had been sold in only 10 states, one of them being Alabama, where Williams lived. Thus, the fibers found on the victims were linked to carpet fibers found in Williams’ home. Source: killers-of-20th-century/
    15. 15. CASE STUDY 2 – THE ATLANTA CHILD MURDERS (1979–1981). Another victim’s body yielded the second type of fiber. This fiber was determined to be from carpeting found in pre-1973 Chevrolets. It was determined that only 680 vehicles registered in Alabama had a matching carpet. Williams owned a 1970 Chevrolet station wagon with matching carpet. The probability of both types of fibers being owned by the same person was calculated. The odds against another person owning both carpet types were about 29 million to one. Williams was convicted and sentenced to two life terms. Source: history-may-22-war-of-roses.html
    16. 16. CASE STUDY 3 – JONBENET RAMSEY CASE (1996). The 1996 homicide investigation of six-year-old JonBenet Ramsey provides valuable lessons in proper crime-scene investigation procedures. From this case, we learn how important it is to secure a crime scene. Key forensic evidence can be lost forever without a secure crime scene. In the Ramsey case, the police in Boulder, Colorado, allowed extensive contamination of the crime scene. Police first thought JonBenet had been kidnapped because of a ransom note found by her mother. For this reason, the police did not search the house until seven hours after the family called 911. The first-responding police officer was investigating the report of the kidnapping. The officer did not think to open the basement door, and so did not discover the murdered body of the girl. Source: dad-regrets-letting-her-do-beauty-pageants/
    17. 17. CASE STUDY 3 – JONBENET RAMSEY CASE (1996). Believing the crime was a kidnapping, the police blocked off JonBenet’s bedroom with yellow and black crime-scene tape to preserve evidence her kidnapper may have left behind. But they did not seal off the rest of the house, which was also part of the crime scene. Then the victim’s father, John Ramsey, discovered his daughter’s body in the basement of the home. He covered her body with a blanket and carried her to the living room. In doing so, he contaminated the crime scene and may have disturbed evidence. That evidence might have identified the killer. Once the body was found, family, friends, and police officers remained close by. The Ramseys and visitors were allowed to move freely around the house. One friend even helped clean the kitchen, wiping down the counters with a spray cleaner—possibly wiping away evidence. Many hours passed before police blocked off the basement room. A pathologist did not examine the body until more than 18 hours after the crime took place. Officers at this crime scene obviously made serious mistakes that may have resulted in the contamination or destruction of evidence. To this day, the crime remains unsolved.
    18. 18. CASE STUDY 3 – JONBENET RAMSEY CASE (1996). 1. What mistakes were made by the Boulder Police Department in securing the crime scene? 2. What specific kinds of evidence may have been compromised? 3. What could the police have done differently to secure the crime scene and the evidence? Source: rents-of-child-beauty-queen-JonBenet-cleared.html
    19. 19. Bertino, A.J. (2012). Forensic Science: Fundamentals and investigations. Melbourne: Cengage Learning. BIBLIOGRAPHY.
    20. 20.