A Complicated Murder Case Solved With the Aid of Fingerprints — Study Notes

Abstract

  • Dubai Police encountered a typical murder case on the date 26th April 201626^{\mathrm{th}}\ \text{April } 2016. The dead body bore strange red marks on the nose and was found tied abruptly on the floor using different types of adhesive tapes.
  • The main challenge was to collect primary evidence like fingerprints and other impressions without disturbing the crime scene.
  • Primary focus was on fingerprints, which can be directly related to individuals involved in the crime.
  • Fingerprint experts were called to the scene to collect and identify all fingerprints from various pieces of evidence.
  • Methods used to develop fingerprints included cyanoacrylate fuming, ninhydrin, and Ardrox dye.
  • The case demonstrated the precision, accuracy, and reliability of the fingerprint experts at the General Department of Forensic Science and Criminology, Dubai Police.
  • AFIS (Automated Fingerprint Identification System) served as a crucial tool in identifying the culprit.
  • Outcome: a total of 2929 fingerprints were collected from the crime scene in less than 24 hours24\text{ hours} and processed for identification.

Introduction

  • Fingerprints have been the benchmark for personal identification in the legal community for over a century.
  • Fingerprints are patterns on fingertips formed by elevated papillary ridges with pores connected to sweat glands.
  • Based on the ‘law of individuality,’ no two people have identical fingerprint patterns in terms of minutiae.
  • Dactyloscopy is the science of using fingerprints and physiological characteristics for identification.
  • Friction ridges and their patterns (fingerprints) provide strong means for personal identification in police work and courts.
  • Types of fingerprints at a crime scene: latent (invisible), patent (visible), and plastic (semi-visible).
  • Advances in computer technology have led to AFIS, which automates interpretation, classification, and coding of fingerprint data.
  • The Automatic Fingerprint Identification System (AFIS) involves fingerprint matching as a core process of the Fingerprint Identification System (FIS).
  • Objective of the case report: to illustrate the role and significance of friction ridge impressions (fingerprints) and to showcase the expertise of Dubai Police forensic specialists.

Background of Case

  • Date and setting: 26 April 2016, a dead body found in an apartment (Figs. 1–3 referenced in the paper).
  • Key scene indicators: body with red marks on the nose, tied to the floor with various types of adhesive tapes, a large water bottle nearby, and a piece of paper with red powder beside the corpse (Fig. 3).
  • Evidence handling: all items were collected with due precautions and sent to the fingerprint division for latent print testing.
  • Visual records: Fig. 1 shows the apartment, Fig. 2 the body’s position, Fig. 3 the body with tape and red-nose marks.
  • Table 1 (Challenges) highlights critical rationales for preserving evidence during processing.

Table 1: Challenges and Rationales (Summary)

  • Challenge: Removing the tape from the body without destroying evidence.
    • Rationale: Avoid tape adhering to itself or other surfaces and prevent destruction of evidence; minimize transfer of dust/dirt from the floor to the tape.
  • Challenge: Transferring the powder from the paper.
    • Rationale: Powder existed in trace amounts; careful transfer to a container for analysis to avoid loss or contamination.
  • Challenge: Identifying suspects and linking the crime within a tight timeframe.
    • Rationale: High case pressure to deliver timely results.
  • A. Challenges faced in the Capsaicin Murder Case: Cases were challenging due to scene complexity and the need to avoid destroying fingerprint evidence.
  • B. Enhancing, Processing, and Lifting Procedures for Fingerprint Impressions:
    • Fingerprint detection strategies depend on surface type and print type (latent, patent, plastic).
    • Oblique lighting is used to locate any latent residues under different angles.
    • Cyanoacrylate fuming (super glue) is widely used to develop latent fingerprints on non-porous surfaces by creating an impression from sweat/oil residues.
    • Post-fuming enhancements include standard fingerprint powders or fluorescent dyes for visibility under UV light and HD photography or photomicrography.
    • Depending on the surface, cyanoacrylate fuming can be followed by powder methods (including magnetic powders) to improve print clarity.
    • The general workflow emphasizes adapting methods to surface characteristics to maximize fingerprint visibility.
  • The above strategies were applied in the present case to maintain evidentiary integrity while maximizing print recovery.

Materials and Methods

  • Setting: Dubai Police Forensic Laboratory employed multiple examination types with attention to destructive vs non-destructive techniques.
  • Sequence of methods applied:
    • Cyanoacrylate fuming on the collected water bottle to develop latent fingerprints on a non-porous surface.
    • Ninhydrin on the piece of paper (porous surface) after careful removal of red powder traces to preserve fingerprint integrity.
    • Ardrox dye post-cyanoacrylate to stain the latent prints, enabling fluorescence under UV and capture with a digital camera.
    • Fingerprint powder applied to the sticky side of adhesive tapes adjacent to suspected areas.
    • AFIS used to compare developed prints against the database to produce a match and identify the suspect(s).
  • Notes on technique selection:
    • Destructive chemical methods (e.g., certain powders and reagents) may preclude other methods on the same area; hence technique choice considered surface type and evidence preservation.
  • Figures referenced for visuals: Fig. 4 (adhesive tape), Fig. 5 (fingerprint on tape), Fig. 6 (disputed document), Fig. 7 (ninhydrin prints on document), Fig. 8–9 (AFIS usage).

Results and Discussions

  • Time-to-identification: The rapid processing and comparison allowed identification within <4\ \text{hours} of arriving at the scene.
  • Print recovery statistics:
    • From the tapes: 1010 fingerprints developed.
    • From the water bottle: 33 fingerprints matched to one of the suspects.
    • From other items: 55 fingerprints paired with a second suspect; 22 fingerprints from the paper matched a third suspect.
    • Overall: 2929 fingerprints were lifted and processed; all were positively identified.
  • Interpretation:
    • Despite the challenging surfaces and evidence the team achieved a conclusive result through careful method selection and rapid processing.
    • The case identified three main suspects associated with the prints.
    • The use of cyanoacrylate fuming was particularly effective given the evidence surfaces.
    • The discussion notes a growing role for nanotechnology trends in fingerprint examination to achieve quick identifications.
  • Practical takeaway: Even minor evidences like fingerprints can be pivotal for solving a crime when properly handled and analyzed with appropriate technologies (e.g., AFIS).

Conclusion

  • Importance of fingerprints in crime scene investigations: The investigation underscored the central role of fingerprint analysis in rapid and reliable identification.
  • On-scene assessment: Initial interpretation suggested death could be linked to homicide, necessitating thorough impression evidence collection for timely analysis.
  • Method effectiveness: Cyanoacrylate fuming was particularly effective for the surface types encountered; other methods (Ninhydrin, Ardrox) complemented analysis on porous and mixed surfaces.
  • Outcome: All evidences yielded clear, positive results linking to three main suspects; the case was solved in under 24 hours24\ \text{hours} using fingerprint evidence alone.
  • Emerging technologies: Nanotechnology trends were highlighted as supportive of rapid fingerprint examination and identification, enabling quick outcomes that might not be possible otherwise.

Future Scope

  • Latent fingerprints are recoverable on a wide range of surfaces regardless of material; method selection remains critical to maximize recovery.
  • Further research directions include nanoparticles and gold-dust-based developments for latent print enhancement and visualization on challenging substrates.
  • There is a need for more studies addressing surface-type dependent effectiveness of different latent print development methods.

Conflict of Interest

  • The authors declare no conflicts of interest or financial/non-financial interests related to the subject matter of this manuscript.

Acknowledgements

  • Acknowledgement of support from Major Expert Saeed Rashid (head of Archive Section), LT assistant expert Yonus Hassan, Senior Expert Dr. Faud Tarbah (head of R&D), and the General Department of Forensic Science and Criminology for their cooperation and assistance.
  • Gratitude extended to the Department of Forensic Sciences, Amity University Dubai for teaching aid and support in shaping the article.

References (Summary)

  • The paper cites references [1] through [21], covering:
    • Fingerprint ridge distance computations, quantitative-qualitative ridge analysis, and models for evaluation.
    • Evidence evaluation in fingerprint comparisons and automated identification systems.
    • Reviews of sequential access methods, altered fingerprints, and orientation field estimation.
    • Reviews of AFIS and automated systems, light-source detection for latent prints, and educational discussions on fingerprint visualization.
    • Techniques and post-processing methods for latent fingerprints, including nanotechnology-based approaches and fluorescent reagents.
    • Classical fingerprint classification and dusting techniques, as well as modern approaches to protein-ligand docking interaction fingerprints in related contexts.
    • Several works on nanotechnology, biosynthesized nano rust for latent print development, and related discussions on future directions in fingerprint science.
  • The References section consolidates foundational and contemporary sources related to fingerprint formation, development techniques, AFIS, and evolving nano-enabled methods.

Visual Aids (Figures Referenced)

  • Fig. 1: Apartment scene
  • Fig. 2: Body position
  • Fig. 3: Body with tape and red powder
  • Fig. 4: Adhesive tape with evidence
  • Fig. 5: Fingerprint developed on tape
  • Fig. 6: Disputed document
  • Fig. 7: Ninhydrin-developed prints on document
  • Fig. 8–9: AFIS usage in suspect identification

Notes on Key Concepts and Terms

  • Dactyloscopy: Science of fingerprint-based identification.
  • AFIS: Automated Fingerprint Identification System, used to compare prints against a database.
  • Cyanoacrylate fuming: A non-destructive process for latent print development on non-porous surfaces by polymerizing cyanoacrylate with moisture and residues.
  • Ninhydrin: Chemical used to develop prints on porous surfaces by reacting with amino acids in sweat to produce a visible print.
  • Ardrox dye: Fluorescent post-stain for prints to enable fluorescent visualization under UV light.
  • Latent vs patent vs plastic prints: Latent impressions require development techniques; patent prints are visible due to residue; plastic prints are impressions in soft materials.
  • Surface considerations: Non-porous surfaces favor cyanoacrylate; porous surfaces favor ninhydrin; mixed or challenging surfaces may require sequential or combined approaches.

Formulae and Quantitative Details (LaTeX)

  • Case timeline and quantities:
    • Date of incident: 26th April 201626^{\mathrm{th}} \ \text{April } 2016
    • Total fingerprints recovered: 2929
    • Time to identification: <24\ \text{hours} from arrival
    • Fingerprints recovered from tapes: 1010
    • Fingerprints matched from water bottle: 33
    • Fingerprints matched to a second suspect: 55
    • Fingerprints matched to a third suspect: 22
    • Suspects identified: 33