1. 1 Instructor: Joseph Hodal, J.D. Crime Scene Investigations II

2. 2 Unit 6: Chapter 9 and 10 Chapter 9: Impression Evidence Chapter 9: Impression Evidence Def: minute imperfections on a large variety of objects such as tools, footwear, tires, and so on produce markings in their normal (and sometimes unusual) usage. These markings are often characteristic of the type of tools or object used. In man instances, very small and sometimes microscopically unique markings are left that can be traced directly to the object or instrument in question. Def: minute imperfections on a large variety of objects such as tools, footwear, tires, and so on produce markings in their normal (and sometimes unusual) usage. These markings are often characteristic of the type of tools or object used. In man instances, very small and sometimes microscopically unique markings are left that can be traced directly to the object or instrument in question. (Fisher, 2004). (Fisher, 2004).

3. Impression evidence Compression Marks Compression Marks Those left when an instrument is in some way pushed or forced into a material capable of picking up an impression of a tool. Those left when an instrument is in some way pushed or forced into a material capable of picking up an impression of a tool. (e.g., shoe impressions, tire impressions, bite mark impressions, fabric impressions, the mark left by a hammer, the mark of a screwdriver, breech mark impressions on shell casings, typewriter marks, etc. (e.g., shoe impressions, tire impressions, bite mark impressions, fabric impressions, the mark left by a hammer, the mark of a screwdriver, breech mark impressions on shell casings, typewriter marks, etc. (Fisher, 2004). Scraping or striated marks Are produced by a combination of pressure and sliding contact by the tool and result in microscopic striations imparted to the surface onto which the tool was worked. (e.g., fired bullets. 3

4. 4 Footprints  Common type of impression evidence found at or near crime scenes. Can indicate whether a suspect was at or near a crime scene.  Note: an investigator should not overlook soil evidence that might later be discovered on the suspect’s shoes.  (Fisher, 2004).

5. 5 Value of Footprints Most valuable details are: Most valuable details are: Signs of wear Signs of wear Characteristic fittings or marks of fitting that have come off Characteristic fittings or marks of fitting that have come off Injuries Injuries Marks of nails and pegs Marks of nails and pegs Especially when they are irregularly placed Especially when they are irregularly placed May lead to an investigative lead. May lead to an investigative lead. (Fisher, 2004). (Fisher, 2004).

6. 6 Footwear

7. 7  Footwear  Shoes and other footwear are valuable items of evidence.  May contain dust, soil, debris, vegetation, or bloodstains on them.  Shoes and other footwear are useful in shoe impressions.  Shoes collected should be packed individually to avoid contamination  Important that the soil is not pulverized or dislodged in transit to lab.  (Fisher, 2004).

8. Foot impressions Foot impressions Generally found outdoors Generally found outdoors 1 st have to protect the impression for alteration or destruction 1 st have to protect the impression for alteration or destruction (e.g., impression in snow are fragile (e.g., impression in snow are fragile Footprints on floors Turn off all lights and use a light directed onto floor at a low angle Easily destroyed (Fisher, 2004). 8 Preservation of footwear and Tire impressions

9. Preservation of footwear evidence Photographing Photographing Casting with dental stone Casting with dental stone Casting with water-filled impressions Casting with water-filled impressions Casting impressions with snow Casting impressions with snow Preservation of footprints (dust prints) Preservation of footprints (dust prints) Recovering the object on which the footprint is made Recovering the object on which the footprint is made Lifting by a special lifter Lifting by a special lifter Lifting by photographic paper Lifting by photographic paper Lifting by static electricity Lifting by static electricity (Fisher, 2004). (Fisher, 2004). 9

10. Taking comparison footprints from a suspect When the original print are from covered feet, e.g., shoes or sneaker, the examiner who makes comparison shoe prints should wear them. When comparison foot prints are taken, the soles are coated with water-based ink using a large ink pad. The inked shoes are then carefully stepped onto a sheet of tracing paper or acetate sheet. (Fisher, 2004). When the original print are from covered feet, e.g., shoes or sneaker, the examiner who makes comparison shoe prints should wear them. When comparison foot prints are taken, the soles are coated with water-based ink using a large ink pad. The inked shoes are then carefully stepped onto a sheet of tracing paper or acetate sheet. (Fisher, 2004). Bare feet impressions are blackened by pressing them against a thing layer of printing ink (Fisher, 2004). Bare feet impressions are blackened by pressing them against a thing layer of printing ink (Fisher, 2004). 10

11. Marks on clothes and parts of the body Fabric marks- must be photographed with scale Fabric marks- must be photographed with scale Tooth marks- leave compression or scraping marks and can occur in butter, cheese, fruit, chocolate and the like. Tooth marks- leave compression or scraping marks and can occur in butter, cheese, fruit, chocolate and the like. Can also occur on the skin of a victim Can also occur on the skin of a victim Preservation of bite marks- Preservation of bite marks- Photography and/or casting Photography and/or casting Casting material for bite mark evidence Casting material for bite mark evidence Human skin vs. foods (Fisher, 2004). Human skin vs. foods (Fisher, 2004). 11

12. Tool marks Marks of tools or of other objects that have been used as tools are often found at the scene of a crime, especially in cases of burglary. Marks of tools or of other objects that have been used as tools are often found at the scene of a crime, especially in cases of burglary. Marks may be left in wood, metal, putty, or paint. Marks may be left in wood, metal, putty, or paint. Tools that leave identifiable marks are axes, knives, screwdrivers, chisels, crowbars, pliers, cutters, and drill bits. Tools that leave identifiable marks are axes, knives, screwdrivers, chisels, crowbars, pliers, cutters, and drill bits. (Fisher, 2004). (Fisher, 2004). 12

13. Preservation of tool marks Whenever possible, tool marks should be kept in their original condition. Can be done by recovering the whole object, or part of the object on which the marks appear. Whenever possible, tool marks should be kept in their original condition. Can be done by recovering the whole object, or part of the object on which the marks appear. Casting tool marks- should be used only as a last resort. No matter how good will not be as good as the original. Casting tool marks- should be used only as a last resort. No matter how good will not be as good as the original. (Fisher, 2004). (Fisher, 2004). 13

14. Trace evidence on tools The tool may also have deposited traces n the form of paint, oil, or other contamination. The tool may also have deposited traces n the form of paint, oil, or other contamination. Traces can be just as valuable as the tool Traces can be just as valuable as the tool Preserving a tool- once found should be preserved for evidentiary value. Preserving a tool- once found should be preserved for evidentiary value. Fragment of tools- examine floor immediately adjacent to the point of entry carefully (Fisher, 2004). Fragment of tools- examine floor immediately adjacent to the point of entry carefully (Fisher, 2004). 14

15. Typed documents Marks from typewriters and check protectors are a special class of tool marks Marks from typewriters and check protectors are a special class of tool marks Can be specific and unique characteristics that may aid in an identification of a class or specific model or instrument used Can be specific and unique characteristics that may aid in an identification of a class or specific model or instrument used (Fisher, 2004). (Fisher, 2004). 15

16. Chapter 10: Firearms Examination Crimes involving the use of firearms represent a significant area of police investigation. Crimes involving the use of firearms represent a significant area of police investigation. Questions: Questions: What kind of weapon was used? What kind of weapon was used? Was the weapon in proper working order? Was the weapon in proper working order? How far away was the weapon fired? How far away was the weapon fired? In what direction was the weapon fired? In what direction was the weapon fired? Did a specific weapon fire a bullet? Did a specific weapon fire a bullet? Did a particular person fire the weapon? Did a particular person fire the weapon? (Fisher, 2004). (Fisher, 2004). 16

17. Characteristics of firearms There are literally thousands of types of firearms There are literally thousands of types of firearms Shoulder firearms Shoulder firearms Rifles and shotguns Rifles and shotguns Hand guns Hand guns Revolvers Revolvers Pistols Pistols Automatic or semiautomatic pistols Automatic or semiautomatic pistols (Fisher, 2004). (Fisher, 2004). 17

18. Ammunition Small arms cartridges or rounds are of two general types: Small arms cartridges or rounds are of two general types: Rim fire – almost exclusively.22 caliber Rim fire – almost exclusively.22 caliber Center fire- almost all other caliber Center fire- almost all other caliber Bullet is the projectile fired from the weapon Bullet is the projectile fired from the weapon Jacket-purpose is to keep the bullet intact and form breaking when it strikes a target, and to prevent damage while in weapon, and to control expansion. (Fisher, 2004). Jacket-purpose is to keep the bullet intact and form breaking when it strikes a target, and to prevent damage while in weapon, and to control expansion. (Fisher, 2004). 18

19. Firearms evidence When a weapon is fired, the firing pin strikes the base of the bullet detonating the primer, which in turn ignites the gunpowder. Expansion of gases forces the casing against the breech, which resists the rearward movement, and propels the bullet down the barrel. The bullet picks up the tiny imperfections of the bore as it passes through. The scratches or striations are caused by the imperfections in the lands and grooves placed in the barrel at the time of manufacture and caused through use of weapon. (Fisher, 2004). When a weapon is fired, the firing pin strikes the base of the bullet detonating the primer, which in turn ignites the gunpowder. Expansion of gases forces the casing against the breech, which resists the rearward movement, and propels the bullet down the barrel. The bullet picks up the tiny imperfections of the bore as it passes through. The scratches or striations are caused by the imperfections in the lands and grooves placed in the barrel at the time of manufacture and caused through use of weapon. (Fisher, 2004). 19

20. Gun Shot Residue (GSR) When the firing pin strikes the base of a cartridge, the shock causes the primer to detonate, in turn causing the ignition of the main gun powder charge. When the firing pin strikes the base of a cartridge, the shock causes the primer to detonate, in turn causing the ignition of the main gun powder charge. The chemical reaction thus started causes a rapid expansion of gases, which propels the bullet out of the barrel of the gun. The by-products of the reaction are burned and unburned powder and the components of the primer mixture. The chemical reaction thus started causes a rapid expansion of gases, which propels the bullet out of the barrel of the gun. The by-products of the reaction are burned and unburned powder and the components of the primer mixture. Primers use shock-sensitive compounds containing such materials as lead, barium, and antimony. Left on a shooters hands. (Fisher, 2004). Primers use shock-sensitive compounds containing such materials as lead, barium, and antimony. Left on a shooters hands. (Fisher, 2004).

21. Gun shot residue

22. Collecting firearms evidence Note locations of shell casings, bullet holes, bullets and bullet fragments, and shotgun shot patterns that are found. Note locations of shell casings, bullet holes, bullets and bullet fragments, and shotgun shot patterns that are found. Vital to the reconstruction of the crime scene and can be used to verify statements by witnesses and suspects. Vital to the reconstruction of the crime scene and can be used to verify statements by witnesses and suspects. Special care must be taken when walking through the location so that casings or bullets are not stepped on, or moved inadvertently. (Fisher, 2004). Special care must be taken when walking through the location so that casings or bullets are not stepped on, or moved inadvertently. (Fisher, 2004). 22

23. Handling firearms Great care must be taken not to destroy evidence Great care must be taken not to destroy evidence Best way to lift a pistol or revolved is to hold it with two fingers on the checkered part of the butt, or possibly the ring of the butt. Best way to lift a pistol or revolved is to hold it with two fingers on the checkered part of the butt, or possibly the ring of the butt. No using a pencil in the barrel No using a pencil in the barrel Should be subjected to preliminary examination of finger prints (Fisher, 2004). Should be subjected to preliminary examination of finger prints (Fisher, 2004). 23

24. After examined for fingerprints After examined for fingerprints Sent to laboratory for firearms testing Sent to laboratory for firearms testing Cartridge cases Cartridge cases Bullets Bullets Marking bullets is important Marking bullets is important Test firing Test firing Powder pattern examination Powder pattern examination National Integrated Ballistic Information Network (Illinois ballistics Information system IBIS) (Fisher, 2004). National Integrated Ballistic Information Network (Illinois ballistics Information system IBIS) (Fisher, 2004). 24

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