Introduction
In the realm of crime scene investigations, light is a versatile tool. Its conversion, which refers to changing light’s wavelength or energy level, is employed in various ways to illuminate critical evidence. On the other hand, the primary objective of using cyanoacrylate fuming is to develop latent fingerprints on non-porous surfaces. Both techniques and an understanding of the necessary preliminary steps for impression casting or lifting are integral to forensic science.
Main Body
A crime scene investigator uses multiple light sources, each emitting a different color or wavelength. The reason behind such a decision is that some substances absorb specific wavelengths and re-emit them at a different wavelength, a phenomenon known as fluorescence, and this is where the conversion of light comes in. By shining a specific wavelength onto a surface, an investigator can cause certain substances to fluoresce, making them visible when they remain unnoticed (Kanodarwala et al., 2021). Examples of substances that can be detected in this way include blood, fibers, and bodily fluids. This technique can also be used to reveal fingerprints dusted with fluorescent powder.
Cyanoacrylate fuming, often known as super glue fuming, is commonly used to reveal latent fingerprints on non-porous surfaces such as plastic, metal, and glass. The technique involves heating cyanoacrylate (super glue) to produce fumes that react with the amino acids, fatty acids, and proteins in the sweat residues left by fingerprints. This reaction forms a white polymer that follows the ridges and patterns of the fingerprint, making them visible to the naked eye (Krishnan & Swart, 2023).
This method is primarily used because it provides highly detailed and resilient fingerprints that can withstand handling and be stored for long periods. In instances where cyanoacrylate fuming may not be suitable, such as on porous surfaces or surfaces that might be adversely affected by the fumes, alternative techniques can be employed. One such alternative is the use of fingerprint powder. The powder adheres to the fingerprint’s sweat residues, allowing it to transfer onto a lifting tape. Another alternative is ninhydrin, which reacts with the amino acids in sweat residues to produce a purple-blue color, making the fingerprint visible.
Before casting or lifting an impression, several steps must be taken. First, the impression must be thoroughly documented with photographs and notes, including measurements and descriptions of its appearance and location. Next, it must be protected from contamination or damage, which might involve covering or cordoning the area. If the impression is in a soft material like mud or snow, it may need to be sprayed with a hardening agent to preserve its details.
Once these steps have been completed, an investigator can cast or lift the impression (Krishnan& Swart, 2023). Casting involves pouring a substance like dental stone or plaster into the impression, which hardens to create a three-dimensional reproduction. Lifting, on the other hand, involves applying a particular tape or gel lifter to the impression and then peeling it off to create a two-dimensional reproduction.
Conclusion
In conclusion, the conversion of light and cyanoacrylate fuming are potent tools in crime scene investigations, each serving a crucial function in evidence detection and collection. Along with the knowledge of the necessary preparatory steps for impression casting or lifting, these techniques allow investigators to uncover and preserve critical forensic evidence, contributing to the pursuit of justice.
References
Kanodarwala, F. K., Leśniewski, A., Olszowska-Łoś, I., Spindler, X., Pieta, I. S., Lennard, C., & Roux, C. (2021). Fingermark detection using upconverting nanoparticles and comparison with cyanoacrylate fuming. Forensic Science International, 326, 110915.
Krishnan, R., & Swart, H. C. (2023). Upconversionluminescence materials for latent fingerprint detection applications in forensic science. In UpconversionNanoparticles (UCNPs) for Functional Applications (pp. 465-489). Springer Nature Singapore.
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