The fragments from 56 pipe bombs were collected (average recovery 87%), counted, weighed, sorted, and photographed. The matrix examined included eight energetic fillers, two initiation systems, three types of pipe, and several degrees of fill. The matrix and results are summarized in Table 1. For identical devices, the overall fragmentation pattern was surprisingly reproducible. The fragmentation patterns are presented in photos, but they are also reduced to numerical evaluators. A particularly useful evaluator is the fragment weight distribution map (FWDM) which describes explosive power with a single variable—the slope. This value is independent of device size and percent recovery. We believe this database of 56 pipe bombs is the largest controlled study of these devices. This study demonstrates the possibility that, even in circumstances where chemical residue cannot be found, sufficient evidence is present in the pipe fragments to identify the nature of the energetic filler.

United States military Composition C-4 explosive contains 91% cyclotrimethylene trinitramine (RDX), 5.3% dioctyl sebacate or adipate (DOS or DOA), 2.1% polyisobutylene (PIB), and 1.6% oil. The original military specification required low viscosity engine oil, but this has since been changed to a specially manufactured mineral oil, also called “process oil.” Differentiation of military and commercial Composition C-4 may be possible by analyzing the oil. In this study, samples of Composition C-4 were taken from various lots of U.S. military M112 demolition blocks from two commercially manufactured brands sold in the U.S. The oil and plasticizer were extracted with pentane, and the plasticizer was removed using silica solid phase extraction cartridges. The oil was then analyzed by high-temperature gas chromatography/mass spectrometry (HTGC/MS). Results indicated that HTGC/MS is an excellent discriminating technique for oil comparisons; however, differentiation of Composition C-4 is limited by manufacturer production and distribution practices.

We have performed experiments that indicate TNT contamination is present on surfaces exposed to TNT vapor, and that TNT contamination is transferred rapidly between proximate surfaces. Contaminated surfaces continue to be nearly constant sources of TNT vapor for some time after removal of the primary source.

The analysis of motor oils has wide applications in the forensic science field from comparing lubricants transferred between an automobile and a victim or crime scene to differentiating the compositions of plastic explosives. In this study, 40 unused motor oils were analyzed and compared by high-temperature gas chromatography-mass spectrometry to determine the potential for oil individualization. Oil samples were also collected from the crankcase dipsticks of 30 cars. Twenty-six of these oils could be differentiated from each other based on visual comparisons of the unresolved envelope (baseline rise due to incomplete separation) and the resolved hydrocarbons in the raw total ion chromatograms (TICs) and smoothed TIC data. Four of these oils were analyzed as unknowns and were correctly related to the corresponding vehicle. The use of extracted ion profiles (EIPs) was explored as a means to further discriminate between the indistinct samples based on the polycyclic aromatic hydrocarbon (PAH) content. The research discussed in this paper demonstrated that differentiation of motor oils was possible by examining the TIC, smoothed TIC, and EIP data.

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