Detection of Fingermarks—Applicability to Metallic Surfaces: A Literature Review

Abstract

There are many different fingermark visualization techniques available, and the choice of methodology employed may be dependent on the surface type. This comprehensive review of the scientific literature evaluates the methodologies of fingermark enhancement methods that are applicable to metallic surfaces; optical, physical, chemical, and physicochemical methods are critically discussed. Methods that are currently used and those that have the potential to reduce the cost and time required to process evidence and increase the recovery rates are considered and are assessed against the Centre for Applied Science and Technology (CAST) and the International Fingerprint Research Group (IFRG) guidelines. The use of chemical imaging techniques in particular has increased the potential to recover fingermarks of sufficient quality for identification purposes. Presently, there appears to be a lack of detailed research pertaining to validation and thorough casework studies for fingermark enhancement techniques. Further studies incorporating these guidelines are recommended.KEYWORDS: forensic science, fingermarks, fingerprints, enhancement techniques, metallic surfaces, latent fingermarks Fingermarks are considered one of the most valuable types of physical evidence recovered from a crime scene. Fingermark casework is still the most common casework for forensic scientists despite the increase in use of DNA (1) to identify/exonerate suspects via bodily fluids (2). The ridge patterns found in fingermarks are permanent and can be used to individualize or exclude suspects from an investigation.Detection of fingermarks on metallic surfaces will be dependent upon the compounds remaining from the fingermark residue. Several detailed reviews have already been published on fingermark composition, but none have focused on fingermarks deposited on metallic surfaces (3,4).Generally, there are two types of fingermarks found at crime scenes: visible fingermarks, usually formed by fingers contaminated by a substance such as oil, fruit, grease, paint or blood, which are deposited on a surface; and latent fingermarks, which are invisible to the naked eye and are the most abundant type of fingermarks at crime scenes. Metallic surfaces are also commonly encountered in crime scenes and are ubiquitous in the environment. Surfaces such as the door of a car, objects like handles, weapons, and tools are usually made of steel. Cartridge cases are frequently recovered from crime scenes and are usually made of brass or nickel (5). There are a number of different techniques that can be applied to a surface to visualize latent fingermarks. The selection of a suitable technique depends on different factors, such as the expected composition of a fingermark, the ability of the chosen technique to be used in tandem with other techniques, and the nature of the substrate. In this review, the focus will be on fingermarks deposited on metallic surfaces, and the optical, physical, chemical, and physicochemical visualization techniques that can be used ...

A low‐potential electrochemical method for fast development of latent fingerprints on brass cartridge cases by electrodeposition of poly(3,4‐ethylenedioxythiophene)

“…[1] Therefore, fingermarks are considered one of the most valuable types of physical evidence recovered from a crime scene, since the personal identity in criminal investigations is still often based on the comparison of a finger impression, or fragment of an impression. [2,3] A major source of fingermark evidence comes from what are typically referred to as latent fingerprints, which are often deposited by individuals when they directly interact with a surface, or handle an object, resulting in the transfer of sweat and other constituents from the hand and fingers onto the object. [4] Metallic objects, such as firearms and cartridge cases as well as knife blades, metal railings, door handles, may be present at crime scenes.…”

Fluorescent polymer nanofibers based on polycaprolactone and dansyl derivatives for development of latent fingerprints

“…Concerning the cartridge cases, such results are encouraging, since currently the success rate in recovering good quality fingerprints from cartridge cases is still quite low, 58 even with the widespread use of the conventional methods for the development of fingerprints, such as, powder, 59 cyanoacrylate, 60 and so forth. Electrochemical methods, for example, electrostatic enhancement, electrolysis and Scanning Kevin microprobe, 61 may also be applied for development of latent fingerprints on cartridge cases; however, these methods are often expensive and require technical refinements that are not available for routine forensic applications, besides a long time (usually hours) for visualization. The electrodeposition of fluorescent conjugated polymers on metallic surfaces arises as a complementary method for enhancement of latent fingerprints under visible and UV light sources 34 F I G U R E 7 Photoluminescence emission spectra of (a) DnsCad in CH 3 CN ( ___ ), PCL/DnsCad 2% (− − -) and PCL/DnsCad 5% ( ….. ) mats with excitation at 335, and (b) DnsGly in CH 3 CN ( ___ ), PCL/DnsGly 2% (− − -) and PCL/DnsGly 5% ( ….. ) mats with excitation at 370 nm.…”

Optimization of Electrochemical Visualization of Latent Fingerprints with Poly(Neutral Red) on Brass Surfaces

“…In contemporary forensics, several techniques are used to visualize latent fingerprints; they are generally divided into optical, physical, physico-chemical, and chemical methods [ 7 , 8 , 9 ]. In addition to conventional techniques (powdering, cyanoacrylate vapors, ninhydrin), some newer and more sophisticated methods are used and described in the studies.…”