In-Lab analysis/analysis of physical evidence
Bullet and Firearms Examinations
Pex Forensic Consulting has it’s own laboratory that conducts specialized examinations on physical evidence. Since many of the cases in which we are retained involve a death. It is not uncommon to have firearms related evidence. Any time a Crime Laboratory identifies a bullet or cartridge case to a particular weapon, it is important to seek confirmation. A match of a bullet or cartridge case to a firearm is direct evidence, just like a fingerprint is direct evidence. Some of the most important cases, however, often are those where the report states the bullet is too badly damaged for comparison or the result was inconclusive. Pex Forensic Consulting has successfully matched bullets that were reported inconclusive by another crime laboratory. We have also encountered situations were an inclusive result was indeed, an exclusion.
Our Services include, but not limited to the examination of bullets, cartridge cases, firearms and clothing. The distance between the end of a firearm muzzle and the victim can often be determined through proximity testing. After the bullet leaves the barrel, unburned gunpowder may also exit the barrel. These may travel up to five feet from the muzzle. As the distance increases, the diameter of the particulate pattern increases.
Crime scene and physical evidence examination requires proper documentation. Video, digital and film photography are all available. Film photography includes UV, Visible, and IR in color and black and white images. Special photography in the UV and IR region changes the contrast of stains on objects. For example, a bloodstain on a black shirt is easily visualized with IR photography. This stain may not be seen by visible light photography.
Some examples of specialized photography are shown here:
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- The photo at bottom right shows a bite mark on a sexual assault victim hand with visible light photography.
- The photo below right shows the tooth penetration in the sin with UV photography.
- The photo at the top left show a puncture wound in normal light.
- Top right, the same puncture wound under ALS light.
Pex Forensic Consulting also performs examinations for biological fluids such as blood and semen. Blood and semen may be difficult to see on dark objects. The use of specialized photography or chemical testing such as Luminol may help locate the biological fluids.
When important evidence is identified, it is always preserved through notes and photography.
This facility can determine location, the type and origin of stains detected on physical evidence. Individualization of stains can be referred to one of several DNA laboratories on the west coast.