In-Depth Notes on Fingerprinting and Forensic Science

Introduction to Fingerprints

• Modern fingerprint analysis goes beyond simply examining prints at a crime scene due to technological advancements.

• Law enforcement can swiftly submit fingerprints to national databases for identification.

• Fingerprints are regarded as largely individual evidence; however, advancements in biometrics enhance identity verification.

History of Fingerprinting

• Ancient Practices:

  • China (3rd Century B.C.): Used fingerprints and palm prints pressed into clay.

  • Babylon (1792–1750 B.C.): Fingerprints were part of clay tablet contracts.

  • China: Kept inked fingerprints on official documents.

• Western Developments:

  • 1684: Earliest record describing finger patterns.

  • 1823: Jan Evangelist Purkinje identified nine distinct fingerprint patterns.

  • 1856: Sir William Herschel noted fingerprint patterns remain unchanged with age.

  • 2014: Facial recognition technology integrated into fingerprint systems with the NGI (Next Generation Identification).

The Science of Fingerprints

• Structure:

  • Ridges on fingers are raised skin portions.

  • Dermal (friction) ridges are responsible for leaving marks when pressed.

• Formation:

  • Finger patterns develop during the 10th week of gestation.

  • Ridge patterns grow from the basal layer and can be altered by scars.

Characteristics of Fingerprints

• Types:

  • Patent fingerprints: Visible prints made by substances like ink or blood.

  • Plastic fingerprints: Indentations created in soft materials (e.g., wax, clay).

  • Latent fingerprints: Not visible without enhancement.

• Basic Ridge Patterns:

  • Loops, Whorls, Arches.

  • Ridge count refers to the number of ridges between the core and delta.

• Minutiae:

  • Unique ridge characteristics important for identification (e.g., ridge endings, bifurcations, and dots).

Collection and Documentation of Fingerprints

• Training for Crime Scene Investigators (CSIs):

  • Learn where to find prints and how to identify and enhance them.

• Collection Methods:

  • Photographing: Use alternative light sources, lasers, and LEDs to capture prints before lifting.

  • Methods for Collecting:

  • Latent Fingerprints: Special techniques to visualize and lift.

  • Patent and Plastic Prints: Utilize various media for direct collection.

Forensic Analysis of Fingerprinting

• Initial Assessment:

  • Conducted by a fingerprint expert to determine quality and features.

• Automated Systems:

  • 1999: IAFIS (Integrated Automated Fingerprint Identification System).

  • 2011: FBI's NGI.

  • 2019: RISC (Repository of Individuals of Special Concern).

• Reliability and Validity:

  • Subjectivity in analysis is present; double-checking results is advised.

• Efforts to Alter Fingerprints:

  • Historical attempts (e.g., John Dillinger used acid to hide prints).

Advances in Fingerprinting

• New technologies improve speed, accuracy, and reliability in fingerprint analysis.

• Digital scanning techniques enhance the identification process significantly.

• Advances include detecting trace DNA and molecular fingerprints for improved identification accuracy.

Summary of Key Points

• Humans have recognized fingerprint patterns for millennia, with modern understanding rooted in ridge formation.

• Fingerprint analysis is essential, with methods in place for proper collection and documentation.

• Current fingerprint technologies have automated much of the analysis, making it faster and more precise.

Memorize the type of fingerprint:

Accidental loop	Plain whorl	Radial loop
Plain arch	Tented Arch	Central Pocket