– Paint Analysis
Scenario: One rainy Saturday evening in a metropolitan urban area, a young mother was crossing a busy intersection pushing her 5 month old baby in a stroller. As she entered the intersection, someone driving a late model black pickup truck came speeding around the corner at a high rate of speed and struck the lady and her child. The mother was killed instantly on contact and the baby was thrown about 20 feet from the point of contact. Miraculously the baby survived and was rushed to the hospital.
When investigators arrived at the crime scene, they were met by two witnesses that said that they saw the entire incident happen. They said that the person who hit the lady and her child was driving a black pickup truck but everything happened so fast that they did not get the license plate number of the vehicle. They told the investigators that they felt that they could identify the driver if they saw him.
About 15 minutes later, officers stopped a man driving a black pickup truck and questioned him about the incident. The man denied any involvement with the incident and agreed to go with the officers to where the two witnesses were. When the two witnesses saw the man, they both positively identified him as the driver of the black pickup truck and further identified his pickup truck as the truck that struck the mother and her child. A black paint chip was recovered from the mother’s clothing to be compared with the sample of paint taken from the man’s pickup truck. Could both witnesses be mistaken about the man and his pickup truck or were the witnesses alert enough to make the positive identification?
This audio will explain how the composition of a chip of paint can be analyzed by its layer structure to reveal if it is consistent with other paint chips that were recovered as part of the investigation. The general myth that all paints of the same color are consistent with each other will be examined and you will understand why this myth is not correct based on the complete analysis of each individual paint chip. This audio will also explain how the powerful instrument known as the Scanning Electron Microscope is utilized to further individualize a paint chip based on its chemical or ionic makeup. You will also find out why a “physical match” is considered to be the most conclusive forensic result in paint analysis.