A mixed DNA profile controversy revisited

Semaan et al. (J Forensic Res, 2020, 11, 453) discuss a mock case “where eight different individuals [P₁ through P₈] could not be excluded in a mixed DNA analysis. Even though … expert DNA mixture analysis software was used.” Two of these are the true donors. The LRs reported are incorrect due to the incorrect entry of propositions into LRmix Studio. This forced the software to account for most of the alleles as drop-in, resulting in LRs 60–70 orders of magnitude larger than expected. P₁, P₂, P₄, P₅, and P₈ can be manually excluded using peak heights. This has relevance when using LRmix which does not use peak heights. We extend the work using the same two reference genotypes who were the true contributors as Semaan et al. (J Forensic Res, 2020, 11, 453). We simulate three two-donor mixtures with peak heights using these two genotypes and analyze using STRmix?. For the simulated 1:1 mixture, one of the non-donors’ LRs supported him being a contributor when no conditioning was used. When considered in combination with any other potential donors (i.e., with conditioning), this non-donor was correctly eliminated. For the 3:1 mixture, all results correctly supported that the non-donors were not contributors. The low-template 4:1 mixture LRs with no conditioning showed support for all eight profiles as donors. However, the results from pair-wise conditioning showed that only the two ground truth donors had LRs supporting that they were contributors to the mixture. We recommend the use of peak heights and conditioning profiles, as this allows better sensitivity and specificity even when the persons share many alleles.     

ICC Pre-Trial Chamber Allows Victims to Participate in the Investigation Phase of Proceedings

The decision rendered by the International Criminal Court (ICC)Pre-Trial Chamber I on 17 January 2006 allows victims to beinvolved in ICC proceedings at an early stage of the investigation.The Prosecutor, who has filed an appeal against this decision,has consistently argued that the right of victims to participatein the proceedings does not cover the investigation phase. Itis argued that the impact of this decision goes far beyond theissue of victims’ participation in the investigations;it has general implications for the balance of power betweenthe judiciary and the prosecution in proceedings before theICC.     

Newspaper juries

This article reports on a field experiment on the effect of media information on people’s attitudes towards the justice system. For the duration of a year a Dutch local newspaper took small groups of readers, called ‘newspaper jurors’, to court sessions of criminal cases and subsequently reported on their experiences and perceptions. Using a quasi-experimental design, we examined whether an attitude change in the general reader population of this particular local newspaper occurred as a result of the jury’s newspaper reports. Findings show that, after the treatment interval of 1 year, no attitude change in the general reader population could be identified that was absent in the control group.     

A rapid gas chromatographic method for the fingerprinting of illicit cocaine samples.

A gas chromatographic (GC) fingerprint method, based on the presence or absence of six congeners, was developed for illicit cocaine samples. The fingerprint utilizes the relative abundances of these congeners towards each other, disregarding cocaine as the main constituent, and can be expressed numerically or graphically in the form of pictograms for rapid visual comparison. The method can be applied directly to a solution of the sample in chloroform, without previous workup procedures. More than 70 unrelated samples were analyzed and a great variation was observed in the parameter composition. On the other hand, a remarkable similarity could be seen between related samples. The GC fingerprint method may be considered an important contribution for sample comparison, as is exemplified by a subdivision of the analyzed samples in different categories, based on the number and types of congeners found.