1. Chapter 4 Fingerprints “Fingerprints cannot lie, but liars can make fingerprints.” - Unknown

2. Objectives Learning Targets: Learning Targets: 1) Define the 3 basic properties that allow identification by fingerprints. 2) Recognize the general ridge patterns and apply them to the primary Henry – FBI classification.

3. At the Crime Scene 1)What is a fingerprint? Fingerprint – impression of the pattern of ridges on the last joint of a person’s finger.

4. At the Crime Scene 2) What are the properties of a fingerprint? –Unique ridges. –Consistent over an individual’s lifetime. –Systematic classification used for fingerprints.

5. Classification of Fingerprints 3) How are fingerprints classified? - 3 basic patterns a) loops b) whorls c) arches

6. Classification of Fingerprints 4) What are loops? Loops – The loop pattern has one or more ridges entering from one side, curving, then going out from the same side it entered. Loops – The loop pattern has one or more ridges entering from one side, curving, then going out from the same side it entered. All loops have a: All loops have a: –Delta – a triangular area usually shaped like the silt formation near the mouth of a river flowing into the sea. –Core – Near the center of the pattern.

7. Classification of Fingerprints 5) What are whorls? Whorls – ALL whorls must have at least 2 deltas and a core Whorls – ALL whorls must have at least 2 deltas and a core 4 whorl groups: 4 whorl groups: – Plain Whorl – Central Pocket – Double – Accidental

8. Classification of Fingerprints 6) What are arches? Arches – friction ridges enter from 1 side of the finger and exit the other side while rising upward in the middle Arches – friction ridges enter from 1 side of the finger and exit the other side while rising upward in the middle Arches do not have a delta or core. Arches do not have a delta or core. 2 types 2 types –Plain Arches –Tented Arches

9. Classification of Fingerprints 7) What is FBI method of classification? Henry – FBI classification – allows all 10 fingerprint types in the world to be divided into common groups. - IMPORTANT: When prints are sent to the FBI, the Henry-FBI classification system allows for the elimination of millions of prints SO that they only have to hand compare a dozen prints.

10. Ridge Classification 8) What are minutiae? Minutiae – fine structure of ridge characteristics Minutiae – fine structure of ridge characteristics pg 57 in your book for different types

11. Presenting Fingerprints as Evidence 9) How are fingerprints used in court? No legal requirements in US on # of points that match No legal requirements in US on # of points that match Criminal courts usually accept 8-12 points Criminal courts usually accept 8-12 points Challenge: 150-200 minutiae in a properly rolled fingerprint, the problem is getting a good, readable print to work with. Challenge: 150-200 minutiae in a properly rolled fingerprint, the problem is getting a good, readable print to work with.

12. Presenting Fingerprints as Evidence 10) What can affect fingerprints? Certain professions can affect a fingerprint Certain professions can affect a fingerprint –Ex. Concrete workers fingerprints become indistinct over time because alkalinity of cement and gypsum can dissolve proteins. John Dillinger (Public Enemy # 1 in 1930) – paid a doctor $5000to dissolve his fingerprints & perform facial surgery John Dillinger (Public Enemy # 1 in 1930) – paid a doctor $5000to dissolve his fingerprints & perform facial surgery

13. Types of Prints 11) What are the 3 types of prints? Plastic prints – indented/molded prints – press a finger into a plastic-like material (i.e. paint, putty, soap) Plastic prints – indented/molded prints – press a finger into a plastic-like material (i.e. paint, putty, soap) Visible prints – left by a finger that has touched, colored material such as blood, paint, ink, etc. Visible prints – left by a finger that has touched, colored material such as blood, paint, ink, etc. Latent prints – essentially invisible & must be developed by chemical/physical means – left by deposits of body oils & perspiration Latent prints – essentially invisible & must be developed by chemical/physical means – left by deposits of body oils & perspiration

14. Visualizing Latent Prints 12) How are prints developed? Dusting – dusting print with a fine powder Dusting – dusting print with a fine powder Chemical methods – chemicals (i.e. iodine, ninhydrin) generally effective for soft, porous surfaces as paper Chemical methods – chemicals (i.e. iodine, ninhydrin) generally effective for soft, porous surfaces as paper

15. The History of Fingerprints 13) When did dactyloscopy begin? Dactyloscopy – study of fingerprints Dactyloscopy – study of fingerprints Started in 19 th century in India with William Herschel Started in 19 th century in India with William Herschel

16. Other Methods 14) What computer program does the FBI use to identify fingerprints? Automated Fingerprint Identification Systems (AFIS) Automated Fingerprint Identification Systems (AFIS)