The Use of Fingerprints in Criminal Investigations

Historical Context

• Date: October 17th, 1902
• Event: Murder of Joseph Reibel at workplace.
• Detection: Detectives found a shard of glass with bloody fingerprints.
• Breakthrough: First time in Europe that fingerprints were used to solve a crime.
• Suspect: Henri Scheffer, arrested for theft, later confessed.

Reliability of Fingerprints

• Common Evidence: Fingerprints are a prevalent form of evidence in criminal courts today.
• Development:
  • Formed in the womb around 7 weeks when skin swells into pads.
  • At 10 weeks, deeper layers grow faster, causing pads to buckle and fold.
  • Influenced by genetics and environmental factors, contributing to unique patterns.
• Uniqueness: Experts believe it’s improbable for two fingerprints to be identical, even among identical twins.

Historical Study and Usage

• Scientific Study: Began in the late 1800s to classify fingerprint features.
• Legal Adoption: Early 1900s saw fingerprints used in court, changing crime scene analysis.

Types of Fingerprints

• Visible Prints:
  • Patent Prints: Left by substances like blood or dirt.
  • Plastic Prints: Impressions in malleable materials (e.g., wax, caulking).
• Latent Prints:
  • Not visible to the naked eye, made of water, oils, proteins, and salts.
  • Revealed by dusting with fine powder or using chemical developers (e.g., Ninhydrin).

Investigative Techniques

• Collection: Investigators collect prints for matching with suspect databases.
• Automated Systems: Used to narrow down potential matches in national databases.
• Expert Comparison: Certified experts analyze ridge details, oil pore spacing, etc.
• Verification: Must be verified by a second expert before being used in court.

Challenges and Limitations

• Issues with Matching: Fingerprints can be smudged, distorted, or overlapped, complicating matches.
• Human Error: A study found a 0.1% false identification rate among fingerprint experts.
• No Universal Standard: Lack of a standard number of ridge details for matches.
• Caution: Investigators stress that no conviction should solely rely on fingerprint evidence.

Future Directions

• Improvements: Forensic experts continue to enhance and standardize the fingerprinting process.
• Significance: Fingerprints have a lasting impact on crime investigation.