Validation of a 16-locus fluorescent multiplex system

STR multiplexes have been indispensable for the efficient genotyping of forensic samples. The PowerPlex 16 System contains the coreCODIS loci, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, THOI, TPOX, vWA, the sex determinant locus, amelogenin, and two pentanucleotide STR loci, Penta D and Penta E. This multiplex satisfies the locus requirements for most national databases and is the most efficient currently available system due to its single PCR amplification. To provide the groundwork for judicial acceptance, including the publication of primer sequences, and to evaluate laboratory-to-laboratory variation, a developmental validation for casework on this commercially available system was performed in 24 laboratories and produced the following conclusions. Amplification was reliable on a variety of thermal cyclers and product could be analyzed on either an ABI PRISM 310 Genetic Analyzer or an ABI PRISM 377 DNA Sequencer. Genotyping using single source samples was consistent between 0.25 and 2 ng of input DNA template with a few laboratories obtaining complete genotypes at 0.0625 ng. However, heterozygote allele imbalance (<60% peak height balance) caused by stochastic effects was observed at a rate of 13% with 0.125 ng DNA and 22% at 0.0625 ng DNA. Mixture analyses were done using a total of 1 ng of DNA template. Most alleles were detected in mixtures of 4 to 1 and some minor alleles were detected in mixtures of 19 to 1. Optimum amplification cycle number was dependent on the sensitivity of the detection instrument used and could also be adjusted to accommodate larger amounts of DNA on solid supports such as FTA paper. Reaction conditions including volume, annealing temperature, and concentrations of primer, AmpliTaq Gold, and magnesium were shown to be optimal yet robust enough to withstand moderate variations without affecting genotype analysis. Environmental, matrix and standard source analyses revealed an ability to obtain complete genotypes in all sample types except those exposed to 80 degrees C for 12-48 days. Finally, comparison of genotype results from the PowerPlex 16 System with other commercially available systems on non-probative reference and forensic samples showed consistent results.     

Suspects,Lies, and Videotape: An Analysis of Authentic High-Stake Liars

This study is one of the very few, and the most extensive to date, which has examined deceptive behavior in a real-life, high-stakes setting. The behavior of 16 suspects in their police interviews has been analyzed. Clips of video footage have been selected where other sources (reliable witness statements and forensic evidence) provide evidence that the suspect lied or told the truth. Truthful and deceptive behaviors were compared. The suspects blinked less frequently and made longer pauses during deceptive clips than during truthful clips. Eye contact was maintained equally for deceptive and truthful clips. These findings negate the popular belief amongst both laypersons and professional lie detectors (such as the police) that liars behave nervously by fidgeting and avoiding eye contact. However, large individual differences were present.     

Detecting Deception in Children's Testimony: Factfinders' Abilities to Reach the Truth in Open Court and Closed-Circuit Trials

This study examined the influence of closed-circuit television (CCTV) on jurors' abilities to detect deception in children's testimony. Children ages 7–9 individually played games and made a video movie with a male confederate. In the guilty condition, stickers were placed on exposed body parts (i.e., the child's arm, toes, and bellybutton). In the not-guilty and deception conditions, stickers were placed on the child's clothing rather than on bare skin. Approximately 3 weeks later, mock jurors recruited from the community viewed child participants testify either in a traditional courtroom setting or via one-way CCTV. The mock jurors responded to questions about the child witness and the defendant as well as deliberated to reach a verdict. Children in the deception condition were asked to testify as if the stickers had been placed on exposed body parts rather than on their clothing. Predeliberation, jurors were less likely to convict when a child testified in the deception condition as opposed to the guilty condition. These differences disappeared following deliberation. There was no support for the notion that jurors reach the truth better when children testify in open court versus via CCTV. Implications for jurors' abilities to reach the truth are discussed.     

The decision to provide discovery: an examination of policies and guilty pleas

Journal of Experimental Criminology - Prosecutors’ decisions to provide discovery can have vast implications for defendants. When prosecutors do not provide exculpatory information in the...     

From European Integration to European Integrity: Should European Law Speak with Just One Voice?

Abstract: This article examines whether and how the moral principle of legal coherence or integrity, which has recently been developed further as a response to disagreement in the national legal context, applies to European law. According to the European integrity principle, all national and European authorities should make sure their decisions cohere with the past decisions of other European and national authorities that create and implement the law of a complex but single European legal order. Only by doing so, it is argued, can the European political and legal community gain true authority and legitimacy in the eyes of the European citizens to whom all these decisions apply. Although European integrity is primarily a product of European integration, it has gradually become one of the requirements of further integration. The article suggests that the principle of European integrity would help dealing with the growing pressure for common European solutions under conditions of increasing diversity. It places disagreement at the centre of European politics, as both an incentive and a means of integration by way of comparison and self‐reflectivity. It constitutes therefore the ideal instrument for a pluralist and flexible further constitutionalisation of the European Union.