1. 15-1 Fingerprinting Chapter 15 Crystal Violet Red Fluorescent Inked Courtesy of C. Fanning

2. 15-2 Prints Making prints Rolling prints Modus operandi Identifying prints Ridge count 3 types- loop, whorl, arch Minutiae Developing and Lifting prints Black, white, fluorescent powders Chemicals-ninhydrin, iodine, silver nitrate, cyanoacrylate Other types of prints

3. 15-3 Patent (Visible) Prints Patent prints are made when fingers touch a surface after the ridges have been in contact with a colored material such as blood, paint, grease, or ink. Inked Crystal Violet Courtesy of C. Fanning

4. 15-4 Plastic Prints Plastic prints are ridge impressions left on a soft material, such as putty, wax, soap, or dust. Locating patent or plastic prints at the crime scene normally presents little problem to the investigator, because these prints are usually distinct and visible to the eye.

5. 15-5 Latent Prints Once the finger touches a surface, body perspiration and/or oils present on the finger ridges are transferred to that surface, leaving an impression. Prints deposited in this manner are invisible to the eye and are commonly referred to as latent or invisible fingerprints.

6. 15-6 Detecting Prints: Nonabsorbent Latent prints deposited on hard and nonabsorbent surfaces (e.g., glass, mirror, tile, and painted wood) can be developed by the application of a powder.

7. 15-7 Detecting Prints: Nonabsorbent Super Glue® fuming develops latent prints on nonabsorbent surfaces, such as metals, glass, electrical tape, leather, and plastic bags. Development occurs when fumes from the glue adhere to the print, usually producing a white latent print. Estimated time: 10 minutes

8. 15-8 Detecting Prints: Absorbent Prints on absorbent surfaces (e.g., papers, cardboard, and cloth) generally require treatment with a chemical. Examiners use various chemical methods to visualize latent prints on absorbent surfaces, such as iodine fuming, ninhydrin, and Physical Developer.

9. 15-9 Detecting Prints: Absorbent Silver nitrate (Physical Developer) --reacts with chlorides to form silver chloride, a material which turns gray when exposed to light.

10. 15-10 Detecting Prints: Absorbent Iodine fuming involves heating iodine crystals that cause vapors which combine with latent prints to make them visible. Iodine prints are not permanent and will fade, making it necessary to photograph the prints immediately. Estimated time: Few minutes Iodine fuming develops latent prints on absorbent and nonabsorbent surfaces, such as paper, cloth, glass, and plastic bags.

11. Place the Object in an Enclosed Container with Iodine Crystals

12. 15-12 Detecting Prints: Absorbent It reacts chemically with trace amounts of amino acids present in latent prints to produce a purple-blue color. Estimated time: 24 hours Ninhydrin develops latent prints on porous surfaces, such as paper and clothing.

13. 15-13 Detecting Prints Once the latent print has been visualized, it must be permanently preserved for future comparison and for possible use as court evidence. A photograph must be taken before any further attempts at preservation are made.

14. 15-14 Lifting Prints If the object is small enough to be transported without destroying the print, it should be preserved in its entirety. Prints on large immovable objects that have been developed with a powder can best be preserved by “lifting” with a broad adhesive tape. Then, the tape is placed on a properly labeled card that provides a good background contrast with the powder.

15. 15-15 Digital Imaging Digital imaging is the process by which a picture is converted into a digital computer file. With the help of digital imaging software, fingerprints, which are often not in perfect condition, can now be enhanced for the most accurate and comprehensive analysis. An important and useful tool, especially for fingerprint identification, is the compare function that places two images side by side and allows the examiner to chart the common features on both images simultaneously.

16. 15-16 AFIS The heart of AFIS technology is the ability of a computer to scan and digitally encode fingerprints so that they can be subject to high-speed computer processing. AFIS aids in classifying and retrieving fingerprints by converting the image of a fingerprint into digital minutiae that contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations).

17. 15-17 AFIS When the search is complete (a computer can make thousands of comparisons per second), the computer produces a list of file prints that must be examined by a trained fingerprint expert. Making your ‘10 Card’

18. How Does AFIS Work? Fingerprint images are scanned and digitized Minutiae are coded Minutiae are searched by computerized matchers Search candidates are produced side-by-side on a computer screen Candidates are examined

19. Ten Card Print Crime Scene Print Algorithm using Minutiae Replaces point ID Uses computers Faster More accurate

20. Other Prints Ears--shape, length and width Shoes--can be compared and identified by type of shoe, brand, size and year of purchase

21. Other Prints Palm-lines can be identified and may be used against suspects.

22. Other Prints Foot Prints are taken at birth as a means of identification for infants.

23. Other Prints Lips--display one of five common patterns  Short vertical lines  Long vertical lines  Rectangular lines that may crisscross  Diamond  Branching

24. Other Prints Teeth--bite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.

25. Other Prints The blood vessel patterns may be unique to individuals. Today they are used for various security purposes.

26. Portfolio A portfolio is a collection of work that demonstrates what you know and can do. It shows your best work. In this unit, you will put together a portfolio of your work on making and lifting various prints. You will add to your portfolio as you work through the labs in class and put it in to a final form at home. You will be given both written instructions and an assessment list.