A Noninvasive and Speculative Method of Visualizing Latent Fingerprint Deposits on Thermal Paper

Latent fingerprint deposits on thermal paper have been visualized noninvasively at visible wavelengths when illuminated with a UV‐A light source (peak 365 nm). A higher intensity UV source (250 W/m² at 0.38 m) gave superior fingerprint visibility when compared with a 60 W/m² (at 0.4 m) source. Removing the visible (blue) component of the light source emission did not adversely affect the visibility of the fingerprint. Sample fingerprints from 100 donors, when examined 24 h after deposition, produced identifiable fingerprints from nearly 34% of fingerprint deposits. A mechanism for the observed visibility is proposed based on low emission of visible wavelengths from areas of thermal paper coincident with the fingerprint deposit, when illuminated with UV. This is likely due to a weak color change in the thermal paper dye arising from protonated amino acid components of the sweat. This effect was not observed on nonthermal paper.     

TrueAllele® Genotype Identification on DNA Mixtures Containing up to Five Unknown Contributors

Computer methods have been developed for mathematically interpreting mixed and low‐template DNA. The genotype modeling approach computationally separates out the contributors to a mixture, with uncertainty represented through probability. Comparison of inferred genotypes calculates a likelihood ratio (LR), which measures identification information. This study statistically examined the genotype modeling performance of Cybergenetics TrueAllele^® computer system. High‐ and low‐template DNA mixtures of known randomized composition containing 2, 3, 4, and 5 contributors were tested. Sensitivity, specificity, and reproducibility were established through LR quantification in each of these eight groups. Covariance analysis found LR behavior to be relatively invariant to DNA amount or contributor number. Analysis of variance found that consistent solutions were produced, once a sufficient number of contributors were considered. This study demonstrates the reliability of TrueAllele interpretation on complex DNA mixtures of representative casework composition. The results can help predict an information outcome for a DNA mixture analysis.     

Caustic Ingestion—A Forensic Overview

The ingestion of corrosive substances may produce severe burns to the upper aerodigestive tract and stomach, particularly if the pH is greater than 12 or less than two. There is a biphasic age grouping with adult cases most often involving self‐harm and pediatric cases accidental ingestion. Three cases are reported to demonstrate characteristic features following the ingestion of potassium hydroxide, glacial acetic acid and Lysol^®, respectively. All deaths were due to the effects of caustic burns to the upper aerodigestive tract, esophagus and stomach with perforation and/or hemorrhage. The extent of injuries in these cases depends on the nature, amount, and concentration of the agent and on the exposure time. A point to note at autopsy is that tissue damage may also occur from postmortem exposure. Typical injuries involve perioral, limb, and trunk burns, with extensive aerodigestive liquefactive/coagulative necrosis causing hemorrhage and perforation.     

Response Assessment of Thermal Papers from Four Continents to Fingerprint Development by Heat

Latent fingerprint deposits on thermal paper sourced from the U.S., China, the U.K., and Australia have been visualized by heating. U.S. and Chinese sourced paper produced two distinct types of fingerprint development. In one type (type 1), the paper dye colors where the deposit is present (as previously reported) and in the other type (type 2) the ‘inverse’ of this gives paper coloring only in areas not coincident with the deposit. Both development types gave identifiable fingerprints, the majority fading within 24 h of heating. Fingerprint development from U.K. and Australian sourced paper was exclusively type 1 and resistant to fading. Temperatures for fingerprint visualization were higher for U.S. paper (64–71°C) and Chinese paper (75–95°C) than for U.K. and Australian sourced paper (43–50°C). Particularly for Chinese sourced paper, these temperatures were within a few degrees of the normal paper color temperature. A mechanism for type 2 fingerprint development is proposed.     

Predilection sites of infantile skull fractures following blunt force

Previous investigations on calvarial fractures in infants have shown that the flexibility and displacement of the infant calvarial are not sufficient to avoid fractures as a result of fall. From a table height onto hard ground - and in special cases, fractures cannot be avoided even after falls onto softly cushioned ground. The skull fractures are located in paper-thin, transparent, single-layer bone areas without diploe. The results of previous literature were compared with investigations of the skulls of 82 infants (from neonates up to infants 14 months of age). Congenital fissures, cranioschisis, locally retarded ossification in the cranium and craniotabes are all weak points where fracture has a tendency to occur even if the impact is minor. These ossification defects are increased in the ossa parietalia, but can also be found in the os frontale or in the os occipitale. The location is not always the same but can be detected by locating the skull transparency using diaphanoscopy.     

The physician assistant as forensic investigator

Physician assistants are employed as forensic investigators at the Office of the Medical Examiner, Suffolk County, New York. We describe the educational qualifications of physician assistants and their valuable role in forensic medicine in Suffolk County.     

CRIMINAL PROPENSITIES,DISCRETE GROUPS OF OFFENDERS,AND PERSISTENCE IN CRIME*

Criminal propensity theorists argue that the causes of variation in offending behavior can be traced to variation in one or more causal traits. Other theorists contend that there is actually more than one type of offender and that more than one causal mechanism operates to explain offending behavior. In this article, some of the implications of these two positions are considered. Then, their congruence with recidivism data from a cohort of post-age-16 North Carolina institutional releasees (N = 848) is assessed, The analysis focuses specifically on whether the correlates of offending persistence are similar across two categories of individuals: those who experienced their first adjudication at an early age and those who were first adjudicated at a later age. In support of both positions, some similarities and some differences in the correlates of persistence were discovered. The differences, however, were only evident when the threshold for late first adjudication was set to age 12. When this threshold was raised to higher ages, the differences disappeared.