Utilizing the urinary 5-HTOL/5-HIAA ratio to determine ethanol origin in civil aviation accident victims

Specimens from fatal aviation accident victims are submitted to the FAA Civil Aerospace Medical Institute for toxicological analysis. During toxicological evaluations, ethanol analysis is performed on all cases. Care must be taken when interpreting a positive ethanol result due to the potential for postmortem ethanol formation. Several indicators of postmortem ethanol formation exist; however, none are completely reliable. The consumption of ethanol has been shown to alter the concentration of two major serotonin metabolites, 5-hydroxytryptophol (5-HTOL) and 5-hydroxyindole-3-acetic acid (5-HIAA). While the 5-HTOL/5-HIAA ratio is normally very low, previous studies using living subjects have demonstrated that the urinary 5-HTOL/5-HIAA ratio is significantly elevated for 11-19 h after acute ethanol ingestion. Recently, our laboratory developed and validated an analytical method for the simultaneous determination of both 5-HTOL and 5-HIAA in forensic urine samples using a simple liquid/liquid extraction and LC/MS/MS and LC/MS/MS/MS. In this previous work a 15 pmol/nmol serotonin metabolite ratio cutoff was established in postmortem urine, below which it could be conclusively determined that no recent antemortem ethanol consumption had occurred. In the current study this newly validated analytical method was applied to five ethanol-positive aviation fatalities where the origin of the ethanol present could not previously be conclusively determined. In four of the five cases examined the detected ethanol was demonstrated to be present due to postmortem microbial formation, and not consumption, even though some indication of ethanol consumption may have been present.     

Defining event reconstruction of digital crime scenes

Event reconstruction plays a critical role in solving physical crimes by explaining why a piece of physical evidence has certain characteristics. With digital crimes, the current focus has been on the recognition and identification of digital evidence using an object's characteristics, but not on the identification of the events that caused the characteristics. This paper examines digital event reconstruction and proposes a process model and procedure that can be used for a digital crime scene. The model has been designed so that it can apply to physical crime scenes, can support the unique aspects of a digital crime scene, and can be implemented in software to automate part of the process. We also examine the differences between physical event reconstruction and digital event reconstruction.     

Validation study of the TrueAllele automated data review system

The New York State Convicted Offender DNA Databank is the first U.S. lab to complete an internal validation of the TrueAllele expert data review system. TrueAllele is designed to assess short tandem repeat (STR) DNA data based on several key features such as peak height, shape, area, and position relative to a standard ladder and use this information to make accurate allele calls. The software then prioritizes the allele calls based on several user-defined rules. As a result, the user need only review low-quality data. The validation of this system consisted of an extensive optimization phase and a large concordance phase. During optimization, the rule settings were tailored to minimize the amount of high-quality data viewed by the user. In the concordance phase, a large dataset was typed in parallel with the ABI software Gene Scan and Genotyper (manual review) and TrueAllele (automated review) for comparison of allele calls and sample state assignment. Only one significant difference was discovered out of 2048 samples in the concordance study. In this case, TrueAllele revealed a spike in the profile that was interpreted as a DNA peak by the analyst in Genotyper. TrueAllele was designed to focus the review on poor data and to eliminate the need for complete reanalysis technical review. This validation project proved TrueAllele to be dependable for use at the NYS Convicted Offender DNA Databank.     

Impact of Defense-Only and Opposing Eyewitness Experts on Juror Judgments

Previous research shows that expert testimony on eyewitness memory influences mock-juror judgments. We examined the extent to which opposing expert testimony mitigates the impact of defense-only expert testimony. Participants (N = 497) viewed a video-taped trial involving an eyewitness identification and individually rendered verdicts and evaluated the evidence and the experts. We manipulated the Foils (unbiased vs. biased) and Instructions (unbiased vs. biased) of the lineup and Expert Testimony (no expert vs. defense-only expert vs. opposing experts). Expert testimony did not significantly influence juror judgments, but the opposing expert testimony diminished the credibility of the defense expert in the eyes of the jurors. Results point to the need for further research on conditions that qualify the impact of expert testimony.     

Priming Unconscious Racial Stereotypes About Adolescent Offenders

Two studies examined unconscious racial stereotypes of decision makers in the juvenile justice system. Police officers (Experiment 1) and juvenile probation officers (Experiment 2) were subliminally exposed to words related to the category Black or to words neutral with respect to race. In a presumably unrelated task, officers read 2 vignettes about a hypothetical adolescent who allegedly committed either a property crime (shoplifting from a convenience store) or an interpersonal crime (assaulting a peer). The race of the offender was left unstated and the scenarios were ambiguous about the causes of the crime. Respondents rated the hypothetical offender on a number of traits (e.g., hostility and immaturity) and made judgments about culpability, expected recidivism, and deserved punishment. They also completed a self-report measure of conscious attitudes about race. As hypothesized, officers in the racial prime condition reported more negative trait ratings, greater culpability, and expected recidivism, and they endorsed harsher punishment than did officers in the neutral condition. The effects of the racial primes were not moderated by consciously held attitudes about African Americans. The implications of the findings for racial disparity in the juvenile justice system and for changing unconscious stereotypes were discussed.