Crime Scene Investigation Types of Evidences Search Pattern

1. Crime Scene Investigation Types of EvidencesSearch Pattern

2. Seven S’s of Crime-Scene Investigation • Securing the Scene • Separating the witnesses • Scanning the Scene • Seeing the Scene • Sketching the scene • Searching for evidence • Securing and collecting evidences

3. Golden Rule in the Crime Scene Investigation and Management • “Never touch, change, or alter anything until it has been secured, documented, identified, measured, photographed and sketched…when a body or object has been moved, it can never be restored to its original position”

4. Types of Evidence • Physical Evidence – encompasses any and all objects that can establish that a crime has been committed or can link a crime and its victim or its perpetrator Evidence can be classified as direct or circumstantial

5. Physical evidence includes impressions such as: -Fingerprints -Footprints -Shoe prints -Tire impressions (skid mark) -Tool marks -Trace evidences (hair, fibers, paint, glass, soil) -Weapons -Bullets and shell casings

6. Direct Evidence- evidence that (if true) proves an alleged fact; includes first hand observations such as eyewitness accounts, confessions, police dash videos. • Circumstantial evidence – is indirect evidence that can be used to imply a fact but that does not directly prove it; it may provide a link between the crime scene and the suspect

7. Circumstantial evidence can be either physical or biological in nature. Biological Evidence includes: -Body fluids -Hair -Plant parts -Natural Fibers

8. Evidence can also be divided into: • Class evidence-narrows an identity to a group of persons or things. Ex. Blood type, hair. • Individual evidence-narrows an identity to a single person or thing. Ex. Fingerprint, handwriting, bullets (striations), toolmarks (striations), shoeprint, tire prints

9. Trace evidence- small but measurable amounts of physical or biological material found at a crime scene. Ex. Hair, skin, clothing fibers, pollen, glass fragments. • Testimonial evidence- includes oral or written statements given to police as well as court testimony by people who witnessed an event.

10. Searching for Evidence • The search pattern selected at a crime scene depends on the size and locale of the scene and the number of collectors participating in the search. Typical examples of crime scene search patterns are: 1. Grid 2. Linear 3. Quadrant or Zone 4. Spiral

12. Collecting Evidences 1. Evidence can be massive or microscopic 2. Evidences may be detected only in a crime lab 3. It is sometimes necessary to confiscate clothing from the victim or perpetrator 4. Critical areas should be vacuumed; sweeping from different areas must be kept separate 5. Fingernail scrapings must be taken from suspects and victim

13. 6. Trace evidence should be left on object unless is attached to a large object; remove with forceps 7. Bloodstains : scraped if dry transfer to moistened swab cut out the area or object 8. Each item must be kept separately 9. All evidences must be properly packaged, sealed and labeled.

14. 10. The evidence log should contain all pertinent information including: -case # -item inventory # -description of the evidence -name of suspect -name of victim -date and time of recovery -signature of person recovering the evidence