Development of a 3D-based automated firearms evidence comparison system

Since the early 1990's, the idea of automated systems for the comparison of microscopic firearms evidence has received considerable attention. The main objective of such systems is to enable the analysis of large amounts of evidence, therefore, transforming the comparison of firearms evidence from an evidence verification tool into a crime-fighting tool. Two such systems have been widely used in United States forensic laboratories: namely, the Integrated Ballistics Identification System (IBIS) (1) and DRUGFIRE (2). Both IBIS and DRUGFIRE have in common the fact that their characterization of a specimen is based on a two-dimensional (2D) representation of the specimen's surface. Although these systems have provided satisfactory results in the identification of cartridge cases, their performance in the identification of bullets has not yet met firearms examiner's expectations. This project was motivated by the premise that a better characterizations of the bullet's surface should translate into better performance of automated identification systems. A three-dimensional (3D) characterization of the bullet's surface is proposed as an alternative to a 2D characterization. This paper discusses the development and preliminary results obtained with SciClops, an automated microscopic comparison system based on the use of a 3D characterization of a bullet's surface.     

An improved method for post-PCR purification for mtDNA sequence analysis

Mitochondrial DNA (mtDNA) analysis of forensic samples typically is performed when the quantity and quality of DNA are insufficient for nuclear DNA analysis or when maternal relatives may be the only reference source. Many of the steps required in the analytical process are both lengthy and labor intensive. Therefore, improvements in the process that reduce labor without compromising the quality of the data are desirable. The current procedure requires purification of the amplicons by centrifugal filtration after PCR and prior to cycle sequencing. Because this method requires several manipulations to perform, alternate cleanup procedures were investigated. These include the use of 1) Qiagen QlAquick PCR Purification columns, 2) Concert Rapid PCR Purification columns, and 3) ExoSAP-IT reagent. When the yield of purified amplicons, quality of the sequence profile, and ease of assay were evaluated, the use of ExoSAP-IT reagent for post-amplification purification was chosen to replace the filtration method.     

Examining the Construct Validity of the Original and Revised JBS: A Cross-Validation of Sample and Method

Factor analysis is a statistical technique that can provide an understanding of construct validity. Previous research examining the factor structure of the Juror Bias Scale (JBS) has uncovered problems in the scale's assessment of the constructs of probability of commission (PC) and reasonable doubt (RD). We here reevaluate the scale's constructs to better our understanding of the pretrial biases involved in the juror decision-making process. Importantly, previous findings have been limited to college student samples and trial material that has involved rape evidence. This study examines the construct validity of the JBS in a sample of 617 jury-eligible adults drawn from the community, and the predictive validity of the JBS is examined across 3 distinct trial scenarios. The results parallel earlier findings, indicating that although RD is a tenable and useful construct affecting juror decision-making, PC may be a less relevant pretrial bias. We therefore suggest that future research emphasize alternative constructs, such as confidence and cynicism in the criminal justice system.     

The spectrum of intramyocardial small vessel disease associated with sudden death

Intramyocardial small vessel abnormalities are not commonly recognized. The best known abnormality is fibromuscular dysplasia involving the sinoatrial or atrioventricular nodal arteries. Small vessel disease has been reported as an isolated cardiac anomaly in individuals with sudden death, and may also be associated with other cardiac conditions including hypertrophic cardiomyopathy and mitral valve prolapse. The nature of the association is unknown, and the mechanism causing sudden death is sometimes obscure. We describe pathological changes of the intramyocardial small vessels of three individuals with sudden death. Abnormalities involved small vessels at different levels. In all the cases, the abnormalities were thought to have caused or contributed to the individual's death. The possible mechanisms of this are discussed.     

Bizarre impalement fatalities--where is the implement?

Two fatalities due to unusual impalement injuries are reported. (1) A large branch broken off during a storm had entered a passing car and perforated the chest of the driver and the back of the seat. The chest organs were grossly lacerated. The car was subsequently stopped by another tree and this second impact removed the wood from the body. (2) A man suffered anorectal impalement by the leg of a stool turned upside down. He had introduced one stool leg into his anus for sexual stimulation and fell onto it. This resulted in a wound channel 36 cm long including perforation of the rectum, urinary bladder, mesentery, transverse mesocolon and liver. Before autopsy, the mode of death was unclear because the man had removed the stool leg himself, his wife had hidden the stool from the scene, and there were no relevant external injuries. In both cases, a reliable reconstruction required investigation of the scene and consideration of extremely unlikely circumstances or of bizarre human activities.     

Evaluation of some oxygen, sulfur, and selenium substituted ninhydrin analogues, nitrophenylninhydrin and benzo[f]furoninhydrin

Six ninhydrin analogues containing oxygen, sulfur, and selenium substituents at the C-5 position, 5-(4-nitrophenyl)ninhydrin, and benzo[f]furoninhydrin were evaluated as fingerprint development reagents. The analogues all showed good fingerprint color development but were not superior to ninhydrin in this respect. The benzo[f]furoninhydrin complex was strongly luminescent at room temperature following zinc complexation, while the remaining analogues required cooling to -196 degrees C to produce optimum luminescence. The benzo[f]furo, nitrophenyl, and methyl selenide analogues showed the best potential as fingerprint reagents with the benzo[f]furo analogue comparing favorably with DFO.