Interdisciplinary cooperation of forensic sciences--results of a simulation exercise

In a workshop held on the occasion of the foundation of the INFW, the Interdisciplinary Network of Forensic Sciences (www.infw.org), 14 scientists from 10 fields of expertise were allotted to 3 teams. Each team had to independently solve the same fictitious forensic case. In this, several corpses or skeletons in varying degrees of decomposition were found in the remains of an old bunker during a large building project. After a set time limit of 45 minutes, the approaches to the task were noted on individual flipcharts by each team. A comparison of the solutions suggested by the three very heterogeneously composed teams revealed a high degree of similarity. However, particularly the "exotic" disciplines developed surprising approaches. The experiment was an interesting and instructive experience for all participants and underscores the necessity of interdisciplinary cooperation in solving complex forensic questions.     

The RECON typology of stalking: reliability and validity based upon a large sample of North American stalkers

A new typology of stalking, RECON (relationship and context-based), is proposed, based upon the prior relationship between the pursuer and the victim, and the context in which the stalking occurs. The static typology yields four groups: Intimate, Acquaintance, Public Figure, and Private Stranger. The typology was tested on a large (N = 1005) nonrandom sample of North American stalkers gathered from prosecutorial agencies, a large police department, an entertainment corporation security department, and the authors' files. Interrater reliability for group assignment was 0.95 (ICC). Discriminant validity (p < 0.01) was demonstrated on a variety of demographic, clinical, pursuit, threat, and violence characteristics among and between groups. Findings confirm and extend the work of other researchers, most notably the very high risk of threats and violence among prior sexually intimate stalkers, the very low risk of threats and violence among public figure (celebrity) stalkers, and the negative relationship between stalking violence and psychosis.     

Three-dimensional surface topography acquisition and analysis for firearm identification

In the last decade, computer-based systems for the comparison of microscopic firearms evidence have been the subject of considerable research work because of their expected capability of supporting the firearms examiner through the automated analysis of large amounts of evidence. The Integrated Ballistics Identification System, which is based on a two-dimensional representation of the specimen surface, has been widely adopted in forensic laboratories worldwide. More recently, some attempts to develop systems based on three-dimensional (3D) representations of the specimen surface have been made, both in the literature and as industrial products, such as BulletTRAX-3D, but fundamental limitations in achieving fully automated identification remain. This work analyzes the advantages and disadvantages of a 3D-based approach by proposing an approach and a prototype system for firearms evidence comparison that is based on the acquisition and analysis of the 3D surface topography of specimens, with particular reference to cartridge cases. The concept of 3D virtual comparison microscope is introduced, whose purpose is not to provide fully automated identification, but to show how the availability of 3D shape information can provide a whole new set of verification means, some of them being described and discussed in this work, specifically, visual enhancement tools and quantitative measurement of shape properties, for supporting, not replacing, the firearm examiner in reaching the final decision.     

Forensic analysis of bicomponent fibers using infrared chemical imaging

The application of infrared chemical imaging to the analysis of bicomponent fibers was evaluated. Eleven nominally bicomponent fibers were examined either side-on or in cross-section. In six of the 11 samples, infrared chemical imaging was able to spatially resolve two spectroscopically distinct regions when the fibers were examined side-on. As well as yielding characteristic infrared spectra of each component, the technique also provided images that clearly illustrated the side-by-side configuration of these components in the fiber. In one case it was possible to prepare and image a cross-section of the fiber, but in general the preparation of fiber cross-sections proved very difficult. In five of the 11 samples, the infrared spectra could be used to identify the overall chemical composition of the fibers, according to a published classification scheme, but the fiber components could not be spatially resolved. Difficulties that are inherent to conventional "single-point" infrared spectroscopy, such as interference fringing and sloping baselines, particularly when analyzing acrylic type fibers, were also encountered in the infrared chemical image analysis of bicomponent fibers. A number of infrared sampling techniques were investigated to overcome these problems, and recommendations for the best sampling technique are given. Chemical imaging results were compared with those obtained using conventional fiber microscopy techniques.     

A simple and inexpensive molecular method for sexing and identification of the forensic samples of elephant origin

The population of the Asian elephant is being dramatically reduced due to poaching of the ivory from the male. As poaching occurs in remote forests, it often takes weeks or longer for it to be discovered and it is therefore often very difficult to determine the sex of the decomposed body. Data suggest that in the recent past, over 2000 male elephants have been poached in South India. We have developed a technique based on molecular markers to determine that the carcass is an elephant and that it is a male. Using DNA sequence information from Genbank, we have developed two primer pairs: one for the mitochondrial DNA (mtDNA) and the other for the sex-determining region of Y chromosome (SRY) gene of the Indian elephant. After PCR amplification of known elephant DNA, we found that the mtDNA was common in both males and females, whereas the SRY-specific amplicon was observed only in the male.