Inherent Fluorescence Detection of Latent Fingermarks by Homemade Shortwave Ultraviolet Laser.

Area of Science:

• Forensic Science
• Analytical Chemistry
• Optics

Background:

• Latent fingermark detection is crucial in criminal investigations.
• Conventional chemical methods risk contaminating or destroying vital biological evidence.
• There is a need for non-destructive detection techniques.

Purpose of the Study:

• To report an optical method for detecting latent fingermarks using UV-excited UV fluorescence.
• To evaluate the effectiveness and sample preservation capabilities of the optical method.
• To demonstrate the practical application of the technique in a real criminal case.

Main Methods:

• Utilized shortwave UV laser excitation to induce long-wave UV fluorescence (300-400 nm) from latent fingermarks.
• Applied the optical method to various paper substrates.
• Documented the successful application in a criminal investigation.

Main Results:

• Achieved a 70-80% recovery rate for latent fingermarks on paper items without chemical treatment.
• The optical method successfully preserved samples for subsequent analyses, including polymerase chain reaction (PCR).
• The technique was instrumental in identifying a suspect in a criminal case.

Conclusions:

• UV-excited UV fluorescence offers a non-destructive and effective approach for latent fingermark detection.
• This method is particularly advantageous when biological information is required for further forensic testing.
• The successful real-world case application highlights the method's potential in forensic investigations.