Forensic Science Progress

Clandestine, or illegal, drug manufacturing laboratories have been established by the criminal element for the purpose of supplying drugs of abuse to the illicit market. This article will review the significant role of forensic scientists in identifying and immobilizing clandestine laboratories. To accomplish this role, the forensic scientist must be familiar with the methods of synthesis for the drugs being produced in these laboratories. As an aide to forensic scientists, the article will examine the drugs being synthesized in clandestine laboratories, the methods of synthesis commonly being used by clandestine laboratory operators, and the methods of chemical analysis that describe significant components present in evidential material seized at these laboratories which enable the method of synthesis to be determined.

From the standpoint of forensic toxicological and criminological examinations, recent analyses of methamphetamine have been reviewed. The literature related to analytical techniques has been divided into two parts. In the first part, attention has been directed to basic and commonly used techniques, including thin layer chromatography, gas chromatography, gas chromatography/mass spectrometry, high performance liquid chromatography, nuclear magnetic resonance spectrometry, and immunoassay. The second part is concerned with practical applications such as examination of enantiomers, illegal drugs, biological samples including hard materials such as hair, nail or bone, and stains of sweat and saliva.

Fibres are probably the most abundant form of trace material. They can be used to provide evidence in a wide variety of criminal cases. The processing of fibre evidence in the forensic science laboratory can be divided into recovery, identification, comparison and evaluation. This article reviews each of these aspects in detail, illustrating how fibre examination has developed over the past two decades. State of the art microscopical and instrumental techniques are presented. Literature concerning fibres and their examination has been extensively reviewed with the intent of providing forensic scientists with a complete, current and concise report on this topic. Background information on dyes, optical brighteners, delustrants and flame retardants is also provided. A section has been devoted to considering é evidential value of fibres. This includes details of colour measurement and the use of data bases. Looking to the future, the increasing production of new fibre types and developments in textile technology which may help forensic scientists are discussed. Microspectrofluorimetry and FTIR-microscopy receive attention as instrumental techniques offering potential for the future. Finally, sources of additional information are provided for several fibre types.

The aim of this critical review was to establish morphologic or biochemical diagnostic markers or indications for the pathogenesis of SIDS in the CNS and to review current literature dealing with CNS changes, especially in the brain stem. The functional disturbances recently discussed as the cause of SIDS, i.e. primary CNS changes in the sense of retardation of neurons in the brain stem, are presented first. Signs of retardation were obtained by quantification of dendritic spines [1, 2] and determination of phenylethanolamine-N-methyltransferase (PNMT), the adrenalin-synthesizing enzyme [3] and disturbances of endorphin immunoreactivity [4, 5]. Dendritic spine density was higher and PNMT activity weaker in the SIDS cases than in the controls, whereas no definitive findings of an increase or decrease in endorphin system activity were found. Signs of secondary CNS changes were established by quantification of the glial cell population in the brain stem [6–8] and determination of Purkinje cell density [9]; some authors found evidence of a brain stem gliosis, but no further indications of chronic systemic hypoxia or chronic hypoperfusion of the CNS could be established in SIDS victims.

Due to differences in the findings as well as methodologic and interpretative problems, no definitive pathogenetic concept based on the available neuropathology findings can be formulated at present, even though many observations tend to indicate that the brain stem, as the central organ controlling respiration, is probably of prime importance in SIDS. Even the classification of the described phenomena as primary and secondary changes can be and is disputed. No diagnostic criteria for classification of SIDS and control cases could be established, since all obtained criteria are nonspecific and the described criteria are not present in all SIDS cases.

The history of forensic science has been characterized by dramatic advances in techniques which enable information to be gleaned from ever smaller quantities of material. Most of the literature is devoted to technical advances, much less attention has been paid to the procedures for interpreting the information objectively and efficiently.

This is a review of the most important advances which have been made in the theory of interpreting scientific evidence in the context of the forensic transfer problem. Increasingly the literature on interpretation employs what is known as Bayesian inference. The Bayesian approach to evaluating transfer evidence is explained and illustrated by simple examples. The problems of communicating a scientific assessment of evidence to a court are briefly discussed.

Any attempts to move towards more objective methods demand background information in various forms and a number of attempts by forensic scientists to establish data collections and to study the nature of evidential transfer are reviewed.

Interpretation is a difficult subject, which is the reason why progress has been slow, but the article attempts to explain some simple principles which should be helpful to any scientist in the field, whatever the discipline.