The presence of low IQ and mental retardation among murder defendants referred for pretrial evaluation

After an overview of definitions of mental retardation and recent case law regarding mental retardation and the death penalty, this paper presents a study of factors associated with a mental retardation (MR) diagnosis among murder defendants. Subjects with a full-scale IQ< or =70 (n=42) were compared with other pretrial murder defendants (n=228) referred for forensic evaluation over a 5-year period. Subjects with an IQ< or =70 who were diagnosed with MR were compared with subjects with an IQ< or =70 who did not receive this diagnosis. Female murder defendants were more likely to receive a diagnosis of MR (p=0.03). MR was also more commonly diagnosed in subjects with an Axis I cognitive disorder (p=0.018). Having an IQ< or =70 was more common in subjects with a psychotic and substance use disorder (p=0.03) and did not necessarily lead to a diagnosis of MR in this subgroup. Implications for diagnosing MR among murder defendants are discussed.     

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.     

Methyl alcohol poisoning in Trabzon (Turkey)

The aim of this retrospective study was to examine methyl alcohol intoxications in Trabzon (Turkey) and to determine any relations between the laboratory results and histopathologic changes. A total of 4492 forensic autopsies were performed from 1998 to 2008. Thirteen of the cases (0.3%) were because of methanol poisoning, and all were men. Their ages ranged from 25 to 62 years. The blood methanol concentrations ranged widely, from 15 to 482 mg/dL. In six cases, poisoning was because of consumption of the alcoholic beverage "Raki," while in five cases, poisoning was because of the ingestion of cologne. The products consumed were unknown in the other two cases because of insufficient history and data records. Mortality because of methanol poisoning may be prevented/decreased with the implementation of some precautions, such as public education regarding the harms of methyl alcohol, routine monitoring of the vendors that sell alcoholic beverages and cologne, and appropriate legal retribution for the illegal production of methanol.     

Multivariate analysis for estimating the age of a bloodstain

Our objective is to provide crime laboratories with a technique for estimating the age of a bloodstain. Toward that goal, we have used multiplexed, real-time RT-PCR (or qPCR) to determine the relative stability of different-sized segments of the same RNA species as well as differences in stability between two different RNAs' change over time in bloodstains. Our results indicate that a multivariate analysis of the changing ratio of the different RNA segments can be used to differentiate between samples of different ages in the defined population. Bloodstains from 29 of 30 donors could be partitioned into different ages using this technique. Although further improvements will be required before this approach can be implemented in crime laboratories, the multivariate analysis holds promise of providing a reliable approach for temporally linking a bloodstain to the commission of a crime or excluding a bloodstain as being irrelevant to the case in question.     

Development of a human-specific real-time PCR assay for the simultaneous quantitation of total genomic and male DNA

A duplex real-time quantitative PCR assay was developed for forensic DNA analysis, which provides simultaneous quantitation of total genomic human DNA and human male DNA. The assay utilizes two spectrally resolved fluorogenic probes in a 5' nuclease (TaqMantrade mark) assay. Within the range of organisms empirically tested and based upon theoretical specificity using National Center for Biotechnology Information GenBank sequences, primer and probe sequences were shown to be human specific, and the Y-chromosome probe, male-specific. A mixture-challenge study resulted in accurate quantitation of 25 pg male DNA in a mixture of up to 1:5000 (male:female DNA). Additional experimental results include comparisons with the slot blot method and commercial real-time PCR kits. The assay developed addresses the shortcomings of the traditional slot blot method as well as the commercial real-time PCR kits. This method is shown to be specific, relatively simple, rapid, has low limits of detection, and consumes limited sample in addition to reporting both the male and total genomic DNA concentrations present.     

Self-inflicted burns: the value of collaboration between medicine and law

Self-inflicted burns are rare in France, but they lead to major, often life-threatening complications. The authors reviewed medical data for patients hospitalized in a burn center from January 2004 to December 2008. Thirty-eight cases of self-inflicted burns were compared with 220 accidental burns. Women were predominantly affected (57.9%, n = 22). A psychiatric history (71%, n = 27) was more frequent in this population. The mean age of the victims was 38 years. The leading method of suicide was flame (94%, n = 36) associated with gasoline used as an accelerant (77.7%, n = 28). Mean total burn surface area (41.5%) and mortality (36.9%) were higher in the self-inflicted burn population. By recognizing epidemiological characteristics and patients at risk, we can better classify lesions related to self-immolation. It is important for the forensic physician to consult survival details to correlate these data with the results of autopsy.     

A Study of the Human Decomposition Sequence in Central Texas*

Abstract: Decomposition studies utilizing nonhuman subjects as human analogues are well established, but fewer studies utilizing intact human remains exist. This study provides data from a controlled decomposition study involving human remains in Central Texas. A 63.5‐kg unmodified cadaver was placed in an open‐air site and observed over a 10‐week period from April 11 through June 19, 2008. A wire enclosure restricted scavenger access. State of decomposition and environmental conditions were recorded daily for the first 36 days and then every 2 weeks thereafter. Results indicated a high degree of correlation with other decomposition studies originating in the southwestern United States, although slight deviations for the average duration of early events were noted. The data were also utilized to test a quantitative method for estimating the postmortem interval. Results indicated preliminary support for a quantitative approach. Additional research is encouraged to further establish the human decomposition data set for Central Texas.     

Sequential monitoring of burials containing small pig cadavers using ground penetrating radar

Ground-penetrating radar (GPR) was used to monitor 12 pig burials in Florida, each of which contained a small pig cadaver. Six of the cadavers were buried in sand at a depth of 0.50-0.60 m, and the other six were buried in sand at a depth of 1.00-1.10 m to represent deep and shallow burials that are generally encountered in forensic scenarios. Four control excavations with no pig interment were also constructed as blank graves and monitored with GPR. The burials were monitored for durations of either 13 or 21 months, and were then excavated to correlate the decomposition state of the cadaver with the GPR imagery. Overall, this study demonstrated that it may be difficult to detect small cadavers buried in sand soon after they are skeletonized because the area surrounding the body, or the grave, may not provide a strong enough contrasting area to be detected by GPR when compared to that of the surrounding undisturbed soil. Also, depth of burial appears to influence grave detection because bodies that are buried at deeper depths may be detected for a longer period of time due to reduced decomposition rates.     

Extraction, derivatization, and analysis of vegetable oils from fire debris

Vegetable oils have the ability to spontaneously heat under certain conditions, which may lead to spontaneous ignition. While the oils are not often encountered in forensic casework, they may be suspected in some fire cases. As these oils are not effectively analyzed using traditional fire debris analysis methods, a protocol must be established for extracting vegetable oils from fire debris. In this study, a protocol was developed for the extraction, derivatization, and analysis of vegetable oils from fire debris. Three derivatization methods were compared to establish an optimal derivatization procedure to convert the fatty acids found in vegetable oils to the fatty acid methyl esters (FAMEs) used in analysis. Three different gas chromatograph columns and programs were examined to determine which was best suited for the separation and analysis of FAMEs. The procedure was tested and refined using a variety of neat and burned vegetable oils, in addition to extractions from oils burned on commonly encountered fire debris materials. The findings of this research will serve as a starting point for further understanding and research of vegetable oils in fire debris.     

Developmental Validation of RSID™-Saliva: A Lateral Flow Immunochromatographic Strip Test for the Forensic Detection of Saliva

Abstract:  Current methods for forensic identification of saliva generally assay for the enzymatic activity of α-amylase, an enzyme long associated with human saliva. Here, we describe the R apid S tain ID entification (RSID™-Saliva), a lateral flow immunochromatographic strip test that uses two antisalivary amylase monoclonal antibodies to detect the presence of salivary amylase, rather than the activity of the enzyme. We demonstrate that RSID™-Saliva is accurate, reproducible, and highly sensitive for human saliva; RSID™-Saliva detects less than 1 μL of saliva. The sensitivity of RSID^TM-Saliva allows investigators to sample a fraction of a questioned stain while retaining the majority for DNA-STR analysis. We demonstrate that RSID™-Saliva identifies saliva from a variety of materials (e.g., cans, bottles, envelopes, and cigarette-butts) and it does not cross-react with blood, semen, urine, or vaginal fluid. RSID™-Saliva is a useful forensic test for determining which evidentiary items contain saliva and thus may yield a DNA profile.