Entity

Time filter

Source Type

Northampton, United Kingdom

Beresford A.L.,University of Leicester | Brown R.M.,University of Leicester | Hillman A.R.,University of Leicester | Bond J.W.,Northamptonshire Police | Bond J.W.,University of Leicester
Journal of Forensic Sciences | Year: 2012

To address the challenge of capturing latent fingerprint evidence from metal surfaces, a new method of latent fingerprint enhancement based on electrochromic polymer films has recently been developed. Here, we present a study comparing the development and visualization of nonvisible fingerprints on stainless steel substrates using this electrochromic enhancement approach with three classical methods (dusting, wet powder, and cyanoacrylate fuming). Two variants of the electrochromic enhancement method were utilized with polyaniline and poly(3,4-ethylenedioxythiophene) as the electrochromic materials. Fingerprint samples were taken from different donors (varying in age and gender) and were exposed to different environments for systematically varied periods of time (up to 28 days). The environments represent plausible evidential scenarios: left under ambient conditions, washed with aqueous soap solution, washed with acetone, submerged in water, and maintained at elevated temperature. The electrochromic enhancement procedure frequently outperformed the traditional methods, particularly for samples exposed to more challenging histories. © 2011 American Academy of Forensic Sciences. Source


Bond J.W.,Northamptonshire Police | Bond J.W.,University of Leicester
Journal of Forensic Sciences | Year: 2011

The reflection of visible light from α-phase brass subject to surface oxidation in air at elevated temperatures is investigated. X-ray photoelectron and auger electron spectroscopy confirm that covered areas of brass (not exposed to air) display dezincification but an absence of significant surface oxidation, confirming a differential oxidation mechanism. Visualization of differential oxidation is shown to be enhanced by selective digital mapping of colors reflected from the surface of the brass using Adobe ® Photoshop ®. Enhancement is optimal when the brass is heated to ∼250°C with areas of oxidation having a mirror-like appearance. The use of this enhancement method to produce a faithful image of fingerprint ridge characteristics is demonstrated on brass shell casings where fingerprints were deposited prefiring. © 2011 American Academy of Forensic Sciences. Source


Shuttlewood A.C.,University of Leicester | Bond J.W.,Northamptonshire Police | Bond J.W.,University of Leicester | Smith L.L.,University of Leicester
Journal of Forensic Sciences | Year: 2011

Previous research has shown that as crime scene location deprivation increases (lower socioeconomic status), the recovery of forensic material, principally DNA and fingerprints, also increases. However, this increase does not result in more crimes being solved by forensic means. In this study, we analyze stolen vehicle data and find a statistically significant positive association between deprivation and the amount of forensic material that matched either the victim or an associate of the victim on a criminal database. The nature of this association was investigated further by inspecting recovered stolen vehicles to establish whether the condition of a stolen vehicle and the tidiness of its interior influenced the recovery of forensic material that was attributed to the victim or an associate. Contradictory results suggest that other factors may contribute to understanding the association between the recovery of victim- or associate-attributable forensic material and crime scene location deprivation. © 2010 American Academy of Forensic Sciences. Source


Bond J.W.,Northamptonshire Police | Bond J.W.,University of Leicester
Journal of Forensic Sciences | Year: 2011

From an examination of the fingerprint sweat corrosion of 40 different individuals on α phase brass, we show that an increase in visualization can be achieved by applying a negative potential to the brass followed by the introduction of a conducting powder. Previously, this technique has been demonstrated only for a positive applied potential and a corrosion product that was dominated by p-type copper (I) oxide. X-ray photoelectron and Auger electron spectroscopic analyses of the surface of the corroded brass show that an increase in visualization with a negative applied potential corresponds with an increase in the concentration of n-type zinc oxide relative to p-type copper (I) oxide with the Cu:Zn ratio <0.8:1. Work function conditions for the formation of an n-type zinc oxide/brass rectifying Schottky barrier are fulfilled. © 2011 American Academy of Forensic Sciences. Source


Goddard A.J.,University of Leicester | Hillman A.R.,University of Leicester | Bond J.W.,Northamptonshire Police | Bond J.W.,University of Leicester
Journal of Forensic Sciences | Year: 2010

The Atomic Force Microscope (AFM) is capable of imaging fingerprint ridges on polished brass substrates at an unprecedented level of detail. While exposure to elevated humidity at ambient or slightly raised temperatures does not change the image appreciably, subsequent brief heating in a flame results in complete loss of the sweat deposit and the appearance of pits and trenches. Localized elemental analysis (using EDAX, coupled with SEM imaging) shows the presence of the constituents of salt in the initial deposits. Together with water and atmospheric oxygen - and with thermal enhancement - these are capable of driving a surface corrosion process. This process is sufficiently localized that it has the potential to generate a durable negative topographical image of the fingerprint. AFM examination of surface regions between ridges revealed small deposits (probably microscopic "spatter" of sweat components or transferred particulates) that may ultimately limit the level of ridge detail analysis. © 2009 American Academy of Forensic Sciences. Source

Discover hidden collaborations