2. 0 CSI You will learn: Processing a Crime Scene (cont.)  Crime Scene Search Methods  The type of evidence that determines what packaging should be used.  Why the chain of custody must be preserved.  Demonstrate proper technique in collecting and packaging trace evidence

3. 1 SEARCH METHODS  Line or strip method—best in large, outdoor scenes  Grid method—basically a double-line search; effective, but time-consuming  Zone method—most effective in houses or buildings; teams are assigned small zones for searching  Spiral method—single person moving inward or outward; best used where there are no physical barriers “A crime scene investigator has to have a positive attitude. You’ve got to believe you are going to find the evidence” - Dr. Henry Lee, Director Forensic Science Laboratory, Meriden, Connecticut Processing a Crime Scene (Step #3) - Search for evidence

8. 6 COLLECTING AND PACKAGING EVIDENCE  Pick up/handle the objects atypically.  Place each item in a separate container, seal, and label.  Collect fragile or transient evidence first.  Wet evidence, such as blood, semen, and saliva, must be air dried first to prevent mold and mildew.  All items of clothing must be air dried then placed in separate paper bags.  The body is the property of the medical examiner. The collection of evidence on the body is done by that department. Processing a Crime Scene(Step #4) - Collect and package evidence, maintaining the chain of custody

9. Packaging Arson Material - metal paint can Blood, Semen, and Saliva (dried) - paper bags Blood (liquid) - glass vial Clothing - paper bag Fingernail Scrapings - envelope, then paper bag Bullets - cardboard box Fibers - envelope, then paper bag Drugs - plastic bag Paint - metal box Soil - paper bag Firearms – Wooden Container

10. 8 CHAIN OF CUSTODY Procedures and documentation used to ensure the integrity of evidence from collection to courtroom presentation.  The number of people handling the evidence should be limited.  The evidence container must be marked for identification.  The collector’s initials should be placed on the seal. Everyone who handles the evidence should initial the packaging with the date.  If evidence is turned over to another person, the transfer must be recorded (to whom, date, time, the reason).  A signed receipt should be obtained from the person accepting evidence.  Conditions of the evidence returned should be noted.

11. 9 CHAIN OF CUSTODY

12. Submit Evidence to Crime Lab Processing a Crime Scene (Step #5) - Submit evidence to the crime lab A forensic lab processes all of the evidence the crime- scene investigation collected to determine the facts of the case. The laboratory results are sent to the lead detective. Test results eventually lead to crime-scene reconstruction

13. Myths Identifying an unknown powdery substance by taste (Taste is not a specific test for ANY drug, and it is dangerous) Chalk line around a body (Not necessary, may not be possible on many surfaces, may destroy evidence. Classically, white or bright yellow chalk is used, although some used paint or white tape. Modern investigators don't do it because it can contaminate the crime-scene by introducing foreign substance.) Collecting a weapon by inserting a pencil into the barrel (Trace evidence inside may get damaged, and the barrel may get marked)

14. 12 CRIME SCENE RECONSTRUCTION Goal: to bring everything together to offer a logical explanation of what took place, the sequence of the occurred events and the positional location of individuals and objects during the crime. Stages (scientific method)  Data collection  Examination, testing, and analysis  Theory formulation (crime scene reconstruction)

15. Outside Scenes  Challenges  Environmental Changes  Animal Intervention  High Traffic Areas  Long Dead  Advantages  Photo/video Cameras

16. Estimating Time of Death  (PMI – PostMortem Interval (Time since death) can be estimated based on body temperature and cooling (algor mortis), rigidity (rigor mortis), settling of the blood and change in color (livor mortis), stomach contents, and presence of insects)  Changes in body after death relates to the ESTIMATION of time of death.  Rigor Mortis  Livor Mortis  Algor Mortis

17. Estimating Time of Death  Livor Mortis – Color of Death 15 Livor mortis is the settling of the blood, causing the skin to change colors. Lividity indicates the position of the body after death. When lividity becomes fixed, then the distribution of the lividity pattern will not change even if the body’s position is altered. Lividity usually becomes fixed between 10 and 15 hours after death.

18. Estimating Time of Death  Livor Mortis – Color of Death 16

19. Estimating Time of Death  Algor Mortis – The Chill of Death 17 Body heat falls after death About 1.5 degrees per hour immediately after death Slowing to less than 1.0 degree per hour after about 12 hours Heat loss is affected by the ambient temperature Corpse (Dead Body) temperature is measured by a thermometer inserted into the liver Time of death is expressed as a range of time

20. Estimating Time of Death  Algor Mortis – The Chill of Death 18 Factors impact Algor Mortis Clothing  Insulates body from heat loss Obesity  Fat insulates, temperature falls more slowly Ratio of surface area to volume  Children, thin people cool faster In water?  Cooling is faster since water is a better conductor of heat than air

21. Estimating Time of Death  Rigor Mortis - Rigidity 19 Temperature Stiffness Time Since of body of body Death Warm Cold Not stiff Stiff Not stiff Not dead more than 3 hrs Dead between 3 and 8 hrs Dead 8 to 36 hours Dead more than 36 hours

22. Myths  Hair and nails continue to grow after death  A dead person’s retinas retain the last image they saw  Rigor mortis causes body to sit up

23. 21 THE CORPSE “The way I see it, being dead is not terribly far off from being on a cruise ship. Most of your time is spent lying on your back. The brain has shut down. The flesh begins to soften. Nothing much new happens, and nothing is expected of you.” — Mary Roach, Stiff. W. W. Norton & Company. 2003

24. 22 THE MEDICAL EXAMINER AND THE CORONER  A medical examiner is a medical doctor, usually a pathologist and is appointed by the governing body of the area.  A coroner is an elected official who occasionally has no special medical training. In four states, the coroner is a medical doctor.