Fingerprint Analysis Quiz

Fingerprint Analysis

• Fingerprints are unique identifiers, each person has different ones, even identical twins
• Fingerprints are used in various ways, including background checks, biometric security, disaster identification, and criminal investigations
• Fingerprint analysis identifies suspects and solves crimes for over a century
• Fingerprints are unique patterns made by friction ridges and furrows on the pads of the fingers and thumbs

Principles of Fingerprint Analysis

• Fingerprints are composed of friction ridges (raised) and furrows (recessed)
• Fingerprint patterns are categorized as loops, whorls, or arches
• Approximately 60% of prints are loops
• Approximately 35% of prints are whorls
• Approximately 5% of prints are arches

Fingerprint Pattern Types

• Loops: Recurve back on themselves to form a loop shape; divided into radial (toward the thumb) and ulnar (toward the pinky
• Whorls: Circulate or spiral patterns, categorized into plain, central pocket loop, double loop, and accidental
• Arches: Wave-like patterns, categorized into plain and tented

Fingerprint Use Cases

• Fingerprint analysis assists investigators in connecting a person to multiple crime scenes
• Fingerprints assist with establishing criminal history records for sentencing
• Biometric security measures (controlling access)
• Identifying victims in mass disasters
• Identifying unknown remains (if fingerprints are on file)
• Background checks for employment or security clearances
• Determining probation, parole, and pardon decisions

How Fingerprints are Used

• Patent Prints: Visible prints are formed from transferred substances like blood, dirt, ink or paint
• Latent Prints: Invisible prints are formed from sweat and oil
• Collecting latent prints often involves dusting with fingerprint powder or chemical processes

Fingerprint Analysis Methods

• Alternate Light Sources (ALS): Laser or LED devices that emit specific wavelengths to visualize latent prints
• Cyanoacrylate Fuming: Exposing a surface to cyanoacrylate vapors, which adheres to latent prints
• Chemical Developers: Using chemicals like ninhydrin (turns prints purple) for porous surfaces and physical developer (for prints involving salts), and DFO for glowing prints under blue-green light
• Other Collection Methods: Special techniques (e.g., vacuum metal deposition) or stains (e.g., Amido Black) for complex surfaces

Fingerprint Analysis Process

• Analysis: Examining the print for suitability and identifying features used for comparison
• Comparison: Examining the latent print against known prints
• Evaluation: Determining whether the prints are from the same source (individualization) or different sources (exclusion) or inconclusive
• Verification: Another examiner independently verifies the analysis and comparisons

Fingerprint Analysis Limitations

• Requires a known print for comparison
• The time of print deposition cannot be determined definitively
• Cannot determine sex, age or race from a latent print

Quality Control and Assurance

• Forensic laboratories implement policies and procedures, analyst qualifications, accreditation standards, and verification processes to ensure accuracy

Expert Witnesses

• Expert witnesses are allowed to provide opinions on scientific evidence in court
• Methods for evaluating expert testimony include the Frye Standard and the Daubert Standard.

Additional Resources

• Websites and publications provide further details and insights on fingerprint analysis and related topics