Classification of firing pin impressions using HOG-SVM.

Crimes, such as robbery and murder, often involve firearms. In order to assist with the investigation into the crime, firearm examiners are asked to determine whether cartridge cases found at a crime scene had been fired from a suspect's firearm. This examination is based on a comparison of the marks left on the surfaces of cartridge cases.

Establishing likelihood ratios for evaluating opposing propositions concerning the activity causing methamphetamine contamination: Smoking or manufacture?

In New Zealand, concerns have been raised over the presence of methamphetamine contamination in households, especially when the activity causing the contamination is unknown. The cause of contamination is also a contentious issue in clandestine laboratory cases concerning charges in relation to "Use of Premises" (Section 12: Misuse of Drugs Act 1975, New Zealand). Regardless of the cause, other than scientific opinion, there is currently no analytical technique that can satisfactorily address the provenance of methamphetamine residues.

Persistence of Polydimethylsiloxane Condom Lubricants.

Polydimethylsiloxane (PDMS) is commonly used to lubricate condoms. The detection of PDMS on swabs from complainants can be used to support an allegation of sexual assault. Previous research has focused on establishing analytical techniques for detecting PDMS.

Application of likelihood ratios for firearm and toolmark analysis.

Historically firearm and toolmark examiners have rendered categorical or inconclusive opinions and eschewed probabilistic ones, especially in the United States. We suggest this practice may no longer be necessary or desirable, and outline an alternative approach that is within a comprehensive logical/Bayesian paradigm. Hypothetical forensic and non-forensic examples are provided for readers who are practicing firearm and toolmark examiners, and the strengths and weaknesses of both approaches are considered.

Experimental design for acquiring relevant data to address the issue of comparing consecutively manufactured tools and firearms.

The comparison of consecutively manufactured tools and firearms has provided much, but not all, of the basis for the profession of firearm and toolmark examination. The authors accept the fundamental soundness of this approach but appeal to the experimental community to close two minor gaps in the experimental procedure. We suggest that "blinding" and attention to appropriateness of other experimental conditions that would consolidate the foundations of our profession.