NCJ Number
222863
Journal
Evidence Technology Magazine Volume: 6 Issue: 2 Dated: March-April 2008 Pages: 34-37
Date Published
March 2008
Length
4 pages
Annotation
Although noting that there are many effective methods for determining the point of convergence for bloodstain patterns (source point for the blood flow that created the bloodstain patterns), the author recommends using inexpensive laser torpedo levels as an easy, quick, and accurate method.
Abstract
These small lasers come with a tripod and a special magnetic cap that converts the laser dot to a visible, continuous line. They also have an on-off switch instead of a momentary switch. These laser torpedo levels can be purchased in a variety of hardware stores, department stores, or on the Internet. They can be mounted onto conventional tripods instead of using the small tripods that come with the product. The lasers the author uses are equipped with a bubble level on the top to allow for alignment to a perfectly horizontal plane. This provides true orientation to the plane of the surface covered by the bloodstains. By using a number of these lasers, the investigator can adjust the lines they project and then align the laser beams through the long axis of each bloodstain to establish a point of convergence. Photographing the result of the laser setup only requires darkening the room slightly in order to brighten the projected laser light. The resulting photos provide a clear documentation of the point of convergence. Some research has shown that in some instances a prolonged exposure to the light emitted from lasers could adversely affect evidence that contains DNA. The author does not believe that the lasers he recommends emit a beam of light sufficiently strong to have such an adverse impact on DNA evidence. In the hypothetical cases described in this article, it took less than 5 minutes for the author to set up the exercise.