Sandia National Laboratories offers a solution. Researchers at the Albuquerque, N.M., laboratory are developing an evidence-detection system that illuminates the natural fluorescence of fingerprints, body fluids and other organic substances that may be clues to a criminal's identity. The system, with the assistance of a flashing lamp and a pair of modified 3-D video game goggles, makes organic substances appear to blink, enabling investigators to locate evidence quickly, even in a lighted room. The proposed system takes advantage of heterodyning, the periodic dissonance between two signals at slightly different frequencies. Existing methods for finding organic evidence can be both difficult and time-consuming. Investigators typically rely on optical aids such as powders, lamps and yellow-tinted goggles that increase the visibility of the evidence. Occasionally, police use fluorescent dyes that can contaminate evidence. The National Institute of Justice, the research arm of the US Department of Justice, has provided $393,000 for the project. Researchers expect to complete a prototype of the detection system within 12 months and make it available for manufacture within 18 months.