(J.W. Birkett). Highlights A list of 136 compounds associated with organic gunshot residue (OGSR) is presented  Recent developments in methods for the extraction and detection of OGSR are highlighted  Analytical techniques aiming to provide a full chemical profile are discussed  It is concluded that the optimal methodology for any OGSR sample should be based on a 'case-by-case' approach 2 Abstract A comprehensive review of the literature concerning all aspects of sampling and analytical techniques used for the determination of organic gunshot residue (OGSR) compounds is presented. Currently, 136 compounds associated with OGSR have been identified in the literature. Despite this area gaining increasing attention and recognition in recent years, there is still an absence of a set combination of sample collection, extraction and analysis methods that are universally optimal for the treatment of any given OGSR sample. Moreover, there are no generally accepted guidelines for selecting the compounds of interest that will inform sampling and analysis protocols. Recent developments in both extraction and analytical methods employed for their detection are highlighted. The main advantages and disadvantages of the sampling and analysis methods are critically discussed.

A review of the literature concerning the fate and behavior of gunshot residue (GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration.

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Abstract-Examination of fracture surfaces near the fbsion crust of the martian meteorite Allan Hills (ALH) 8400 1 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed structures strongly resembling mycelium. These structures were compared with similar structures found in Antarctic cryptoendolithic communities. On morphology alone, we conclude that these features are not only terrestrial in origin but probably belong to a member of the Actinomycetales, which we consider was introduced during the Antarctic residency of this meteorite. If true, this is the first documented account of terrestrial microbial activity within a meteorite from the Antarctic blue ice fields. These structures, however, d o not bear any resemblance to those postulated to be martian biota, although they are a probable source of the organic contaminants previously reported in this meteorite.