The Recovery of Latent Fingermarks from Evidence Exposed to Ionizing Radiation*

Abstract: Continual reports of illicit trafficking incidents involving radioactive materials have prompted authorities to consider the likelihood of forensic evidence being exposed to radiation. In this study, we investigated the ability to recover latent fingermark evidence from a variety of substrates that were exposed to ionizing radiation. Fingermarks deposited on common surfaces, including aluminum, glass, office paper, and plastic, were exposed to doses ranging from 1 to 1000 kGy, in an effort to simulate realistic situations where evidence is exposed to significant doses of radiation from sources used in a criminal act. The fingermarks were processed using routine fingermark detection techniques. With the exception of glass and aluminum substrates, radiolysis had a considerable effect on the quality of the developed fingermarks. The damage to ridge characteristics can, in part, be attributed to chemical interactions between the substrate and the components of the fingermark secretions that react with the detection reagents.     

Biological and DNA evidence in 1000 sexual assault cases

Using a Filemaker-based database (DNA Pro-FILES, Synchrone Infosystème Inc.), we have conducted a large-scale study on 1000 sexual assault (SA) cases where a standardized kit was submitted to our laboratory alone or with other types of exhibits. We looked at the likelihood of obtaining good quality DNA evidence, allegedly from the assailant, according to a number of parameters.The overall proportion of SA cases with DNA evidence is nearly 50%. A little more than 30% of SA kits provided DNA evidence while for 16% of cases DNA evidence could be obtained only from other exhibits.The likelihood of obtaining DNA evidence is approximately 50% in teenager and adult SA cases, but much lower for children 10 years old or younger (15%). In children cases, profiles were found mostly on clothing or skin swabs.The likelihood of obtaining DNA evidence from vaginal swabs remains good for up to 3 days after the assault (from 35% on the first day to 23% on the third day). A DNA profile was obtained from approximately 22% of anal/rectal swabs and 41% of skin swabs taken less than 1 day after the assault. Less than 10% of oral washes provided DNA evidence, all having been collected within 24 h of the assault.We found that in bodily samples, a negative result for acid phosphate (AP) is a poor predictor of the likelihood of obtaining good quality DNA evidence. Approximately 15% of vaginal swabs and 8% of anal swabs negative for AP nevertheless provided good quality DNA evidence.     

Evaluation of iodine-benzoflavone and ruthenium tetroxide spray reagents for the detection of latent fingermarks at the crime scene

The performance of two spray reagents, iodine-benzoflavone and ruthenium tetroxide (RTX), was evaluated and compared with the conventional technique currently used at the crime scene, that is, powdering. Neither the spray techniques nor powdering were shown to be suitable for all surfaces and ages of marks tested. On some surfaces such as glass and treated wood, powdering was still the superior technique, whereas the spray techniques produced better development on wallpaper, vinyl, and brick. Sequencing work showed that RTX was incompatible with powdering and cyanoacrylate (with a rhodamine 6G stain). Iodine-benzoflavone can be used successfully either before or after powdering in a sequence; however, it was incompatible with cyanoacrylate. Two non-CFC formulations of iodine-benzoflavone using HFC4310mee and HFE7100 solvents were tested and shown not to be as effective as the original Arklone (CFC-113) formulation; however, the HFC4310mee solvent is recommended as the most suitable replacement solvent. Due to the expense of the commercial RTX spray, attempts at formulating a more cost-effective version were also carried out. A formulation was developed that gave comparable development to the commercial version but at a much cheaper cost, and with a shelf life of up to two months. Recommendations are presented for which techniques are suitable for different surfaces and ages of marks. Powdering was shown to be the best technique on all ages of marks tested on treated wood, glass, and also on marks aged three days and older on paint. Iodine-benzoflavone was the best technique on wallpaper, vinyl, brick, and raw wood. RTX was the best detection technique for fresh marks and marks aged up to one day on wallpaper and paint.     

Forensic applications of chemical imaging: latent fingerprint detection using visible absorption and luminescence

Chemical imaging technology is a rapid examination technique that combines molecular spectroscopy and digital imaging, providing information on morphology, composition, structure, and concentration of a material. Among many other applications, chemical imaging offers an array of novel analytical testing methods, which limits sample preparation and provides high-quality imaging data essential in the detection of latent fingerprints. Luminescence chemical imaging and visible absorbance chemical imaging have been successfully applied to ninhydrin, DFO, cyanoacrylate, and luminescent dye-treated latent fingerprints, demonstrating the potential of this technology to aid forensic investigations. In addition, visible absorption chemical imaging has been applied successfully to visualize untreated latent fingerprints.     

An evaluation of the Maxcan fibre finder version 3.3 on cotton fibres

The Maxcan fibre finder system is a product of Cox Analytical Systems, Sweden, and has been developed for the primary purpose of searching for fibres on tape lifts. This paper evaluates the ability of the Maxcan system to search for different fibre types and colours under varying conditions. The system performed effectively in most situations, although it did have problems with some search combinations that a human operator would also find difficult in a manual search. The Maxcan system has the added advantages of being objective, consistent and able to do large batch searches unattended. These attributes make it very useful where a large number of tapes need to be searched in casework and also in research where large quantities of data need to be gathered within a reasonable time.     

A further study to investigate the detection and enhancement of latent fingerprints using visible absorption and luminescence chemical imaging

This study investigated the application of chemical imaging to the detection of latent fingerprints using the Condor macroscopic chemical imaging system (ChemImage Corp., Pittsburgh, USA). Methods were developed and optimised for the visualisation of untreated latent fingerprints and fingerprints processed with DFO, ninhydrin, cyanoacrylate, and cyanoacrylate plus rhodamine 6G stain. The results obtained with chemical imaging were compared to the detection achieved using conventional imaging techniques. The Condor significantly improved the detection of many prints, especially those that might be considered poor quality or borderline prints. Prints on newspaper treated with ninhydrin and DFO, and prints on white and yellow paper treated with ninhydrin, benefited the most from chemical imaging detection. In many cases, fingerprints undetectable using conventional imaging techniques could be visualised with chemical imaging. Ridge detail from untreated prints on yellow paper was also detected using the Condor. When prints of high quality were examined, both detection techniques produced quality results. The results of this project demonstrate that chemical imaging offers advantages over conventional visualisation techniques when examining latent fingerprints, especially those that would be considered difficult, such as weak prints or prints on surfaces that produce highly luminescent backgrounds. Standard testing procedures for the detection and enhancement of fingerprints by chemical imaging are presented and discussed.     

Predicting the Onset of Sexual and Drug Risk Behaviors in HIV-Negative Youths with HIV-Positive Mothers: The Role of Contextual,Self-Regulation,and Social-Interaction Factors

HIV-negative, inner-city adolescents with HIV-infected parents are considered to be at high risk for acquiring HIV themselves. Using a modified theory of health behavior, this study examined the effects of maternal HIV infection and psychosocial variables on the onset of sexual and drug risk behavior in 144 HIV-negative adolescents with and without HIV-positive mothers. Adolescents and their mothers were interviewed when the youths were 10–14 years old and again when they were 13–19 years old. By follow-up, 42% of youths reported the onset of vaginal sex (vs 5% at baseline). Marijuana and alcohol use increased from 6 and 38%, respectively, at baseline to 25 and 60% at follow-up. Among those reporting risk behaviors, 40--50% reported onset prior to 14 years. Youth and family psychosocial variables, but not maternal HIV status, were associated with risk behaviour outcomes. Claude A. Mellins research interests include mental health, psychosocial, and public effects of maternal and pediatric HIV; interventions for HIV-affected families; and adherence. Curtis Dolezal research interests include HIV-related sexual behavior in a variety of populations with a particular emphasis on methodology/measurement issues. Elizabeth Brackis-Cott research interests include impact of HIV/AIDS on the lives of children and families directly affected by the disease. Ouzama Nicholson research interests include international public health and pediatric HIV infection and operational issues in developing effective prevention of mother-to-child transmission of HIV infection and pediatric HIV care programs. Patricia Warne research interests include program development, structural interventions for HIV, and policy. Heino F. L. Meyer-Bahlburg research interests include psychosexual assessment, the development and determinants of sexual risk behavior, and the effects of HIV disease on sexual functioning.     

Comptes Rendus Book Reviews

This article follows the efforts of white settlers to impose cotton as an export crop in Natal and Zululand. Touted as a commodity capable of remaking land and life in the region in the 1850s, the 1860s, and again in the 1910s and 1920s, cotton never achieved more than marginal status in the region's agricultural economy. Its story is one of historical amnesia: although faith in the region's cotton prospects dipped following each spectacular failure, it was routinely resurrected once previous failures had been accounted for, or memories of them had faded.

Two crucial issues are at the centre of this episodic history. First, I explore the logistics of planned expansion, and the reasons for the repeated collapse of cotton-growing schemes. Second, I unravel the side effects of these difficult and disappointing efforts and argue that, despite repeated failure, cotton facilitated important structural changes to the region's agricultural, political and economic landscape.