Midwest Forensics Resource Center 2006 Funded Projects
Latent print examiners in the United States utilize a methodology called ACE-V. This is an acronym for Analysis, Comparison, Evaluation, and Verification. The objective of the project is to measure variation between examiners during the opinion-forming stages of ACE-V. We will statistically evaluate the results (both the conclusions and the basis for the conclusion) of experts examining several side-by-side comparisons of latent prints and known exemplars, under various conditions. The experiment will be repeated with non-experts and the results of both groups compared. Additional background information will be collected from the participants (e.g. training, experience, sex) for further comparison of the results.
Solution stability data will be collected for liquid samples from various stages of methamphetamine production using the Iodine/Red phosphorus reaction scheme. Solution aliquots will be stored at four distinct storage conditions: Refrigerated (5ºC), Ambient, Controlled Room Temperature (25ºC/60% RH), and Elevated Room Temperature (40ºC). Sample solutions will be pulled at defined time-points up to twelve (12) months and analyzed by gas chromatography – mass spectrometry (GC-MS) to determine concentration trends of ephedrine, pseudoephedrine, and methamphetamine. Results of the analyses will be used to evaluate the precursor and final product stability based on specific sample storage conditions coupled with length of storage.
Final Report
Currently video cameras are widely used as a tool for recording criminal acts. Due to recent enormous advances in analog and digital editing technologies, digital editing or fabrication of videotape evidence has become possible. Today fine magnetic particles or ferrofluids are used to visualize any artificial alteration on magnetic tapes such as tape recorder ‘start’ and ‘stop’ marks and over-recordings. However, the use of magnetic particles and ferrofluids is time consuming, inaccurate, and can easily cause contamination or even damage on the surface of tape evidence. We propose a new forensic imaging technique which will allow fast and accurate analysis of magnetic tapes using a transparent magnetic garnet film. The garnet film replaces the magnetic particles or ferrofluids for visualization of magnetic fields and gives a non-invasive method of detection with a high spatial resolution and fast inspection time.
The low cost of our previous ultra-fast (cycle time = 3 min.), reversed-phase gradient HPLC separations of mixtures of regulated intoxicants along with its extraordinary, previously unachieved, (= 0.002 min. standard deviation) short-term (within day and between batches of eluent) retention repeatability ought to make it a practical, reliable and more selective screening method for drugs of abuse. We now propose to study the long term reproducibility of retention, to develop a chemometrically based approach to automate analyte identification based on diode-array UV spectra, and to test the methodology by running an extensive series of comparisons on actual positive and negative samples in collaboration with the Minnesota Bureau of Criminal Apprehension (BCA).
The comparative forensic sciences are under attack for lacking a scientific basis. Objective observations are believed to be subjectively interpreted. This pilot undertaking may afford the criminal justice system a tool in providing hard science for the objective statement of probability, in either exculpating or incriminating a suspect from patterned injuries caused by human teeth. Although deoxyribonucleic acid (DNA) can be associated with a human bite, it is not always recovered as a link. The significance is that with a large number of additional exemplars analyzed, a database could be produced from which the human dentition can be virtually individualized.
Final Report
This proposed research concerns a new instrument to detect the presence and precise location of clandestinely buried bodies. Human decomposition produces a range of chemical by-products, these can indicate the presence of human remains. Traditionally detection of such a broad range of chemicals is performed with advanced and complicated instruments (GC-MS, HPLC, etc.). It is proposed herein to perform the first step in developing a portable instrument using pyrolysis, low power portable sensors, and/or pattern recognition to detect these chemicals. The end instrument will have both a Surface Sweep (for general area) and Cone Pentrometer (for specific location and verification).
Final Report
Micromechanical cantilever (MC) based sensors can provide revolutionary sensitivity for forensic detection and identification of controlled substances, toxic species, biological molecules and DNA matching. Current sensor systems require extensive sample preparation and/or specialized instrumentation to identify molecules of controlled substances such as cocaine with high specificity and sensitivity. We aim to overcome these limitations by developing robust miniature sensors based on high-resolution interferometry coupled with aptamer-based receptor layers. In order to demonstrate the feasibility and forensic suitability of our approach, we will develop MC-based sensor for sensitive and specific identification of cocaine molecules.
Final Report
The overall objective of this study is to show that crystal orientation can be used to match metal fracture surfaces and conclude that they were one piece of metal prior to fracturing. Electron Back-Scattered Diffraction (EBSD) is used to determine the orientation of the individual crystals. The outcome of this project will be a workable map of the orientation pattern of crystals along the fracture surfaces of metals.
Final Report