Brooke Kammrath, assistant director of the Henry C. Lee Institute of Forensic Science at the University of New Haven, outlined the case of Gary Ridgway to prove that the analysis of paint is extremely important in forensics.
Kammrath spoke at the University of Rhode Island’s Forensic Science Seminar Series. Her lecture, titled “Forensic Analysis of Paint”, took place on March 25 at 3:30 p.m. in the Beaupre Center for Chemical & Forensic Sciences.
Ridgway, the infamous Green River Killer of Seattle, was sentenced to life in prison in 2003 after murdering women since 1982. The microscopic analysis of spray paint led to his final conviction after many years. In the mid 1980s, Ridgway was shockingly put and taken off of the suspect list after passing a polygraph test.
Automotive paint is the most commonly found type of paint evidence, according to Kammrath. However, other cases involving artwork and forgery, spray paint and burglary can require the forensic analysis of paint. This paint evidence can take the form of paint chips, smears in the result of contact and aerosol spheres from spray paint like the ones found in the Green River Killer case.
According to Kammrath, her diverse collection of chemistry interests all play a part in analyzing paint.
“It’s one of those complex materials that makes it exciting every day to analyze,” Kammrath said.
Kammrath discussed the structure of paint and how it affects the process for forensic analyzers. She explained that paint not only has 5 main chemical components, but also 3-4 physical layers. Properties of the components and layers create a diverse collection of paints around the world.
She emphasized that the development of paint is constantly changing on top of having complex analytical chemistry. Types of paint vary geographically as well as over time. Forensic analyzers find paint sample matches to solve cases, but the variety makes it difficult to decide on evidentiary significance.
According to Kammrath, the most popular color of car was brown in the 1970s, red in the 1980s and has been white for the past two decades. However, this is not the case in other countries, which makes the variety of paint even more complicated. Kammrath also said that automotive paint companies rarely disclose the chemical and physical properties of the paint they manufacture.
“If we’re trying to judge the significance of a paint association, knowing how the paint changes overtime means that we are never getting an equilibrium,” Kammrath said.
Forensic analyzers utilize microscopic procedures and flowcharts to help determine evidentiary significance while solving a case. According to Kammrath, they can assist themselves using paint color databases and color popularity studies. However, there are limited resources due to paint’s developing nature in the world.
With these difficulties, it is the analyzer’s effort and diligence that helps solve forensic cases involving paint.
“The amount of information we are able to get from a paint sample really depends on how far we go with the analytical chemistry,” Kammrath said.
Over time, two-colored cars, custom paint types, and car wraps have increasingly become popular. According to Kammrath, the variety of paint continues to increase, but the popularization of custom automotive paint increases too. The increase in custom paint makes automotive paint differentiable and therefore reliable evidence. This helps forensic analyzers slightly in the ever-changing world of paint
The Forensic Science Seminar Series will continue every Friday at 3:30 p.m. until April 25. The next lecture will take place on Friday, April 1. It is titled “Forensic Medical Examination” and will be led by former state medical examiner Priya Banerjee.