Intentional mixed buccal cell reference sample in a paternity case

We report a case where an alleged father (AF) attempted to substitute someone else's saliva sample for his reference sample in a paternity analysis. Buccal cells were collected from the AF and the child, and DNA analysis was performed using an autosomal STR loci (Identifiler). The profile from the AF showed extra peaks in some loci, as well as a much higher "X" allele peak relative to the "Y" allele peak at the amelogenin locus. After conducting reanalysis by another technician with another set of positive and negative controls, it was concluded that the only source of the mixed profile was by intentional introduction by the AF, at the time of sampling, of some foreign human biological material, most likely saliva from a woman. Owing to the inconclusive results, when the AF was called back to the lab and the peculiar results were explained to him, he admitted that he had introduced into his mouth saliva from another person in an attempt to be excluded as the father of the child. Although tampering with DNA reference samples is not common, some individuals may attempt to contaminate or otherwise adulterate specimens before DNA tests. Personnel responsible for sampling should be aware of this possibility and should try to establish procedures to avoid the problem.     

Paths to destruction: the lives and crimes of two serial killers

Although research into the phenomenon of serial murder has revealed that serial killers frequently do not fit the initially described paradigm in terms of their physical and psychological profiles, backgrounds, and motives to kill, the media continues to sensationalize the figures of such killers and the investigators who attempt to analyze them on the basis of aspects of their crimes. Although the so-called "typical" profile of the serial murderer has proven accurate in some instances, in many other cases the demographics and behaviors of these killers have deviated widely from the generalized assumptions. This report details two unusual cases in which five and eight murders were committed in upstate New York. The lives and crimes of these offenders illustrate the wide spectrum of variations in the backgrounds, demographics, motivations, and actions witnessed among serial murderers, and highlight the limitations and dangers of profiling based on generalities.     

Visual detection of trace nitroaromatic explosive residue using photoluminescent metallole-containing polymers

The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4-dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole-containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (lambda(em) approximately 400-510 nm) in the presence of the explosive is seen immediately upon illumination with near-UV light (lambda(ex)=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.     

Diagnostic dilemma of sudden deaths due to acute hemorrhagic pancreatitis

Sudden death due to acute pancreatitis has been rarely determined. A review of 3305 autopsies performed between 1991 and 2001 at the Council of Forensic Medicine found 12 cases (0.36%) with sudden death due to acute hemorrhagic pancreatitis without symptoms. A history of chronic alcohol ingestion was obtained from family in four cases (33%), and no stones were found in the bile ducts or in the gall bladders. During the autopsies, hemorrhage and edema were localized on the head of the pancreas in three cases and the whole pancreas in nine cases. The most common extrapancreatic pathology was found in the lung including pulmonary edema, alveolar hemorrhage, pleural effusion, and pulmonary congestion. There was no correlation between pulmonary and pancreatic damage. It is suggested that the forensic pathologists who are dealing with sudden unexpected death must not ignore the examination of pancreatic and extrapancreatic regions to avoid missing acute pancreatitis.     

Heat Induced Changes to Dental Resin Composites: A Reference in Forensic Investigations?*

The objective was to investigate color change and surface damage in dental resin composites exposed to high temperatures over different time intervals for comparative purposes. Samples were prepared using two resins - Z100(R) (R1) and Charisma (R2), heated at the following temperatures: 200 degrees C, 400 degrees C, 600 degrees C, 1000 degrees C, for 15, 30 and 45 min (n = 104 for each resin sample). Color (DeltaE) and brightness (DeltaL) changes were analyzed by spectrophotometry using the CIE Lab system and surface changes by Scanning Electron Microscopy (SEM). R1 showed more intense color changes after heat exposure than R2. DeltaL values were found to be the best parameter for evaluation of light and color change. A biphasic pattern after thermal exposure was detected, from dark brown to light white. SEM showed more intense alterations in R2 than in R1. These results indicate that the parameters observed in both resins are useful as a guide in forensic analyses.     

Measuring the intercondylar shelf angle using radiographs: intra- and inter-observer error tests of reliability

This study presents a test of intra- and inter-observer measurement error rates of the intercondylar shelf angle of the distal femur, as measured on lateral radiographs. This measurement is the central element of a method to determine racial affiliation from the distal femur. Four observers independently radiographed a set of 33 complete and partial femora from collections housed at the Joint POW/MIA Accounting Command, Central Identification Laboratory. Each observer then measured the intercondylar shelf angles in each radiograph, following the original method's guidelines. A supplementary inter-observer error test was conducted by four additional observers on one set of radiographs. Statistically significant differences were found for both intra- and inter-observer error based on the results of Student's t-tests, paired samples t-tests, and ANOVA analyses. The results of this study indicate that further experimentation should be undertaken in order to develop refined measurement techniques that may help improve standardization and reduce the observer error rates.     

Psychological adjustment in a forensic sample: relationship with approach- and avoidance-coping typologies

Most studies that relate coping strategies with psychological symptoms usually consider a single coping dimension. This means that interpretation of the results is unclear and only partially true as subjects activate different types of coping strategies simultaneously when faced with a stressor. The objective of the present study is to analyze the relationships between coping and psychopathology in young inmates, taking into account the number of approach and avoidance answers simultaneously. The results show that the inmates with above-average scores in avoidance coping and below average in those of approach (coping responses inventory--adult form, [CRI-A]) show higher symptomatology (MMPI-2) than the inmates who obtain above-average scores in both avoidance and approach strategies. It can be deduced that it is not the high use of avoidance coping that is related to psychopathology, but rather the combined use of many avoidance strategies and few approach strategies. The convenience of jointly taking into account both types of coping is discussed.     

Passport examination by polarized infrared spectra

In this study, a new nondestructive technique for passport examination is proposed. In this technique, linearly polarized light is used to measure Fourier transform infrared (FT-IR) reflectance spectra of films on the biographical data page. Thirty genuine and thirty-five counterfeit Japanese passports and five marketed films pasted on name cards were examined. The measured spectra were analyzed as follows. The absorption spectra were obtained by the Kramers-Kronig transformations of reflectance spectra. The peak ratios were then calculated from the absorption spectra by adding the peak areas at 1126 and 1263 cm(-1) and dividing the result by the peak area at 1727 cm(-1). When nonpolarized light was used, the samples could not be distinguished by comparing the peak ratios. However, when polarized light was used, they were successfully distinguished by the comparison. Therefore, polarized light is useful for the forensic discrimination of passport films by the measurement of FT-IR spectra.     

Gunshot residue in Chicago police vehicles and facilities: an empirical study

Suspects in shooting investigations in Chicago are routinely transported in department vehicles and detained in department facilities prior to gunshot residue (GSR) evidence collection. The GSR test results are used to associate the suspect with primary exposure to GSR. The potential for these vehicles and facilities being sources of secondary GSR contamination needed to be determined. A total of 201 samples were collected from randomly selected vehicles and detention facilities. The sampling collected trace materials from surfaces that suspects' hands may contact during the arrest process. These samples were examined for the presence of GSR particles using scanning electron microscopy. Upon completion of the automated analysis, those particles that met an initial GSR screening criterion were relocated and reanalyzed. The locations where GSR particles were recovered allowed us to make recommendations to the Chicago Police Department with regard to transporting and detaining these suspects. The low number of GSR particles recovered suggests that the potential for secondary contamination, although present, is relatively low.     

Age estimation by a dental method: a comparison of Lamendin's and Prince & Ubelaker's technique

Lamendin et al. (J Forensic Sci 1992;37:1373) developed a general technique to estimate age of adults at death using two dental features: periodontosis and translucency of the tooth root. Prince and Ubelaker (J Forensic Sci 2002;47:107) modified this method, creating a formula for each sex and for different ancestries, and obtained more precise age estimations. In the present study, the validity of each method was tested in 45 males and 34 females of Spanish Caucasian origin, and a novel formula, based on Prince and Ubelaker method, was specifically developed for a population of mixed racial origin (mestizo) from Colombia, and findings obtained were again compared with those yielded by Lamendin adult dental aging technique. The Prince and Ubelaker method proved more accurate than the Lamendin technique in the Spanish Caucasian population, and our Prince and Ubelaker-based formula was also more accurate than the Lamendin et al. In both populations, the Lamendin method showed a higher mean error in estimations of the age of youngest and oldest individuals. These findings confirm the need to create specific formulas for each human group in order to obtain more accurate age estimates.