Midwest Forensics Resource Center 2005 Funded Projects
This project will examine the elemental composition of automobile body fillers, body putties, and caulking-type materials, by Laser Ablation-Inductively Coupled-Mass Spectrometry (LA-ICP-MS) and investigate if the trace element signatures can provide sufficient information to enable a forensic analyst to make a decision, either inclusion or exclusion, when comparing a questioned sample to a standard sample. This project will also develop criteria and protocols for the comparison and differentiation of these sample types and present the framework for a systematic scheme for elemental characterization of these materials.
The majority of explosive devices that are dealt with by law enforcement agencies within the United States fall into the area of what is referred to as “Improvised Explosive Devices” or IED’s. These refer to explosive devices that are clandestinely manufactured from materials that can be bought in hardware stores and other common locations. By having a database that contains data regarding manufacturer stamps and other information that can be found on the various types of pipes and tubing that can be used to manufacture IED’s available to both investigators at the scene, as well as laboratory personnel examining bombing debris, the chances for successful resolution of a bombing incident are greatly increased.
Forensic soil comparison has traditionally been performed via mineralogical analysis. Any water or organic soluble fractions of soil are typically disregarded in forensic comparisons. Methods for high performance liquid chromatographic (HPLC) analysis of organic and humic materials in soil have been developed but their discriminatory power has not been demonstrated in the literature. Ion chromatography (IC) has been utilized for detection of water soluble inorganic anions in forensic explosive analysis but has not been utilized in forensic soil comparisons. This study will examine qualitative variation in acetonitrile soluble organic fractions of soil and quantitative variation in inorganic anions such as nitrate, chlorate and perchlorate in soil. Quantitative analysis of inorganic anions will also provide information regarding baseline levels of these materials in rural, suburban and urban areas which will assist forensic scientists in data interpretation in the analysis of low explosives in soil samples.
The premise that particular manufacturing methods produce marks on tools that are substantially different from tool to tool is generally accepted by the toolmark examiner community. This premise is empirically based on a handful of limited studies in the literature and years of training and practice by examiners. The purpose of this research is to help objectively establish validation of the “machined-surface uniqueness” premise by refining statistical algorithms that were developed under an earlier feasibility study funded by the FBI, and applying them to a large database of previously collected digital images representing several different manufacturing process.