Copy of Unit 3 Study Guide PDF

Unit 3: Fingerprints Study Guide Due on test day Use the Independent Study Packet to fill in these answers (40 points) Learning Intentions Success Criteria I will: I...

Unit 3: Fingerprints Study Guide Due on test day Use the Independent Study Packet to fill in these answers (40 points) Learning Intentions Success Criteria I will: I can correctly: Identify different types of fingerprints and the Identify different types of prints based on minutiae in a fingerprint. minutiae Identify a suspect based on fingerprint Perform one different method of obtaining comparison fingerprints Explain the different methods of obtaining fingerprints I can demonstrate the use of magnetic powder in dusting for prints 1. The fundamental principles of fingerprints: a. Individuality: Every fingerprint is unique and no two individuals, including identical twins, have the same fingerprints. b. Permanence: Fingerprints do not change over time; they remain consistent throughout a person's life. c. Patterns: Fingerprints can be systematically classified into patterns such as loops, whorls, and arches. 2. Describe the formation of fingerprints based on the video. Fingerprints are formed in the womb during fetal development. The ridges are influenced by the movement of the fetus and the pressure from the surrounding environment. 3. The purpose of fingerprints is a. They provide a unique identifier for individuals, used in forensic identification. b. Prints are also found: On various surfaces such as glass, metal, and fabric. 4. Fingerprints cannot be removed because The ridges in the skin regenerate if the outer layer is damaged, making it impossible to permanently remove them. 5. Fingerprinting is individual evidence, meaning it puts you into specific Person. 6. Identify the three classess of fingerprints and their subdivisions. Type Drawing Descriptions ARCH Plain Arch Smooth rise in the center. Tented Arch Sharp upthrust in the center. Type Drawing Descriptions LOOP Ulnar Loop Loop opens towards the little finger. Radial Loop Loop opens towards the thumb. WHORL Plain Whorl Circular ridges. Central Pocket Loop with a central circular ridge. Whorl Double Loop Two loop formations intertwined. Whorl Accidental Does not fit into other categories. Whorl 7. Describe the use for fingerprints in investigations: Fingerprints are used to positively identify individuals at crime scenes. They serve as a reliable form of physical evidence that can place a suspect at the scene or prove their involvement. 8. Define ridgeology: Ridgeology is the study of the unique patterns of ridges on fingers, focusing on the analysis of ridges, valleys, and minutiae for identification purposes. 9. A fingerprint is made of a series of ridges and valleys on the surface of the finger. The uniqueness of a fingerprint can be determined by the patterns of ridges and valleys as well as the minutiae points, which are points where the ridge structure changes. 10. Describe the importance of identifying minutiae in a case. Minutiae are the key to determining the individuality of a fingerprint. Comparing specific minutiae points allows forensic analysts to match prints to a suspect with a high degree of accuracy. 11. How many points of similarity do the US and international courts accept for a match? The number of accepted points of similarity varies, but many US courts look for at least 8-12 points, while some international standards may require more. 12. Describe AFIS and its importance. AFIS (Automated Fingerprint Identification System) is a digital system used to store, search, and compare fingerprints in a database. It significantly speeds up the process of identifying suspects by matching unknown prints to those on record. 13. Identify and draw the types of minutiae. Minutiae Drawing Ridge ending Island Bridge Lake or enclosure delta fork dot spur  14. Label the minutiae in this image. 15. Other than fingerprints, describe other prints that are accurate in linking a suspect to a crime scene. Other prints include palm prints, footprints, and lip prints. 16. Describe the importance of a latent print. Latent prints are invisible until developed. They are important because they can show someone was at the scene. 17. Describe each type of print development listed below: Development Description Powders/dusting Powders stick to the oils in fingerprints, making them visible. Iodine Iodine fumes react with oils, showing prints on paper. Ninydrin Turns prints purple by reacting with sweat on paper. Silver nitrate Reacts with salt in sweat to show prints under UV light. Cyanoacrylate The fumes stick to prints, making them white on surfaces like glass or plastic. Notes: Introduction to Fingerprints Definition and Importance of Fingerprints A fingerprint is an imprint made by the ridge patterns on the tip of a finger, serving as a unique identifier for individuals. Fingerprints are useful in forensic science due to their unique characteristics, which provide individual evidence in criminal investigations. They remain consistent over a person's lifetime, making them reliable for identification purposes. Fingerprints can be systematically classified, aiding in the organization and retrieval of fingerprint data. Basic Fingerprint Patterns Arch: Friction ridges enter on one side and cross to the other, rising upward in the middle; least common type (5%). Loop: Ridges enter from one side, curve around, and exit from the same side; most common type (65%). ○ Types of Loops: Radial (opens toward thumb) and Ulna (opens toward pinky). Whorl: At least one ridge makes a complete circuit; found in 30% of the population, more common in individuals of Asian descent. ○ Types of Whorls: Plain, central pocket, double, and accidental. Minutiae and Ridge Characteristics Understanding Minutiae Minutiae are the small, detailed characteristics of ridge patterns that help in the identification of fingerprints. Common types of minutiae include ridge endings, bifurcations, and dots, which are crucial for fingerprint analysis.  The analysis of minutiae allows forensic experts to compare and match fingerprints effectively. Recording and Classifying Prints Fingerprints can be recorded using rolling inked prints or electronically, facilitating easier classification and storage. The classification of prints is essential for forensic databases and criminal investigations. Types of Prints Beyond Fingerprints Other Types of Biometric Prints Palm Prints: Friction ridges on palms can be identified and used similarly to fingerprints. Lip Prints: Exhibit several common patterns but are not unique to individuals. Voice Prints: Electronic pulses measured on a spectrograph can identify individuals based on voice characteristics. Shoe Prints: Can be compared by type, brand, size, year of purchase, and wear patterns, aiding in criminal investigations. Footprints: Size and friction ridges can provide information, though they are not unique. Unique Identifiers in Forensics Earprints: Unique patterns can help catch criminals. Bite Marks: Unique dental imprints can be matched to suspects. Eyeprints: Blood vessel patterns in the eye are unique and used for security purposes. Latent Prints and Development Techniques Understanding Latent Prints Latent prints are not visible to the naked eye and are caused by the transfer of oils from fingers to surfaces. They require development through chemical or physical means to become visible for analysis. Techniques for Developing Latent Prints 1. Powders: Adhere to water and fatty deposits; best on hard, nonabsorbent surfaces. 2. Iodine Fuming: Produces temporary yellow-brown prints; effective on porous paper. 3. Ninhydrin: Reacts with amino acids to produce orange to purple prints; best on porous surfaces. 4. Silver Nitrate and UV Light: Forms silver chloride, turning gray when exposed to light; effective on porous materials. 5. Cyanoacrylate (Superglue): Forms a hard deposit that can be enhanced for visibility. Automated Fingerprint Identification System (AFIS) Overview of AFIS AFIS stands for Automated Fingerprint Identification System, established in the 1970s to store and retrieve fingerprints. It allows for searching files for a set of prints and comparing single prints from crime scenes. The system has evolved into IAFIS, an international database for fingerprint identification.