AbstractsLaw & Legal Studies

Bloodstain evidence can be obscured and lost when deposited on dark surfaces where there is no contrast between the bloodstain and the surface. This can also occur when criminals attempt to conceal bloodstains by painting over them. This research investigated the detection and visualization of bloodstains deposited on dark surfaces and concealed under paint with the use of an infrared (IR) alternate light source produced by the Foster and Freeman company under the name Crime-lite^® 82S Infrared. The results show that the Crime-lite^® 82S Infrared in conjunction with an IR sensitive camera can aid in the detection and visualization of bloodstains best on porous surfaces such as indoor carpets and most clothing as well as on and under red-tinged paints with the more flat or matte finishes. The results also suggest the component within blood responsible for absorbing IR light is hemoglobin present in red blood cells. Further, the findings indicate that when hemoglobin is present in too low of a quantity, it falls below the detection threshold to absorb IR light and bloodstains will not be visualized. Given its ease-of-use and portability, combined with the support of the findings from this collaborative study with the Los Angeles Police Department (LAPD) Field Investigation Unit (FIU), the Crime-lite^® 82S Infrared and camera is recommended as an additional tool in the search for bloodstain evidence that may otherwise go undetected.