Paint & Coatings Industry - November 2008 - (Page 76)

Paint and Criminal Forensic Science (including the truck) was sent to the trace analysis unit for additional work. Once there, a paint/plastic pigmented impact transfer was found on the left knee of the boyfriend’s pants. The transfer coincided physically and chemically with a fabric impression on the left under-side of the dashboard, next to the steering column of the pickup truck. A few days of work and photography inside the truck, reconstructing the moment of the accident impact and, using lab employees as “dummies”, showed that the girlfriend was the passenger, not the driver. A day later, the girl was released from jail. The boyfriend coincidentally confessed to a cousin, in another state, that he had been the truck driver, but he disappeared and has yet to be found. The case was rewarding from a trace evidence perspective, but the husband of the deceased woman is still unconsoled. Case Example Four – The Green River Murders Many other examples of forensic paint analysis abound, and can involve artistic, automotive OEM, repaint, historical, maintenance and architectural finishes – and just about anything else the readers of this magazine have, can or will develop. A notable example grew out of the Green River Murders case in King County, Washington. Gary Ridgway murdered approximately 50 women during a two- or three-year period in the early 1980s, but had not been charged or tried for those crimes. Many of the victims had been dumped into the Green River outside Seattle. Twenty years later, Skip Palenik, principal of Microtrace LLC in Elgin, IL, was called into the cold case. He was asked to peruse the known victims’ clothing evidence, which had been previously The newest innovation in a high speed dispersion blade is called the TURBO POLYBLADE, an abrasion resistant blade with shear pegs molded as part of the blade. 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Box 3, Wyncote, PA 19095 • 800-726-1366 • 215-635-1366 • Fax 215-635-6355 sales@norstoneinc.com • www.NorstoneInc.com All Major Credit Cards Accepted analyzed unsuccessfully, and then held in storage those 20 long years. He and his former assistant, Sarah (Walbridge) Jones, applied micro vacuuming techniques to the clothing, and recovered hundreds of polyurethane paint mist spheres in a wide variety of colors. This writer, and Dr. Brezinski of PCI, were called into the case by the King County prosecutors to assist in evaluating the evidence, analyzing current products and searching for historical paint samples from the early 1980s. Gary Ridgway, who was an early suspect in the original investigation, had been a custom tractor spray painter in Seattle’s Kenworth painting plant. The prosecution assertion became that Ridgway, who worked in the open-air spray paint shop, collected the mist on his clothing, and transferred it to his victims during his assaults. The micrometer-sized mist paint particles were analyzed using micro-infrared spectrometry and visible light spectroscopy, and found to be similar to the 2K paint systems Kenworth was using when Ridgway worked for them. Chemists from Dupont were invaluable in supplying known pigment and paint formulations they had produced for Kenworth at the time of the murders. Company data banks of old formulations and even retained paint samples can be of immeasurable historic and forensic value. Overwhelmed with the paint evidence, Ridgway subsequently confessed before trial and, to avoid the death penalty, led authorities to many murder sites that were previously undiscovered. He apologized for not remembering all of them. These cases (with a few changes to protect privacy) show some of the challenges and rewards of criminal forensic paint examination. Similar stories of micro-analysis challenges and successes can be told about examinations involving all the other types of materials trace examiners are called to analyze. It’s a rewarding profession. For more information, contact Mike at microfor@ fastq.com. Visit ads.pcimag.com 74 pci10082Norstone.indd 1 NOV EMBER 2008 | W W W . P C I M A G . C O M 9/12/08 10:32:02 AM http://www.NorstoneInc.com http://www.NorstoneInc.com http://ads.pcimag.com http://WWW.PCIMAG.COM

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Paint and Coatings Industry - November 2008 Contents Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News HiTone Resins for Enhanced Pigment Affinity of Powder Coatings New Water-Based Interior Coatings Combine Innovation and Quality With Respect for the Environment Novel, UV-Curable Nanotechnology-Enabled Coatings Highly Weather-Resistant Radiation-Curable Monomers and Oligomers for Exterior Applications Konica Minolta — Sensing Success for Viracon Self-Crosslinkable Thermosetting Acrylics for Use in Water-Dilutable Coatings Paint and Criminal Forensic Science Supplier and Application/Curing Showcases Materials Watch Classifieds Advertiser Index

Paint & Coatings Industry - November 2008

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