Comdex brings to the Sands Expo Center, in Las Vegas, a lot of expensive computer equipment and a lot of opportunities for crime. So Frank Strocchia, whose company provides security for the trade show behemoth, was not surprised last November when an exhibitor reported the theft of a $2,000 Pentium PC. But the president of SOA Security was surprised when the exhibitor's product helped catch the thieves.

The product was Gotcha! from Prescient Systems, of Menlo Park, Calif. Gotcha! is motion-activated surveillance software that works with any video-recording device to record everything from burglary to less-than-stellar employee behavior. The evening before the theft, the Gotcha! sales team left the program running on two computers at their booth. That night, two men entered the expo center and took one of the computers but left the other. A digital camera wired to the PC captured their activities, and Gotcha! stored the video on its hard drive. The next morning, the Prescient team played the video file for Strocchia, who recognized the thieves. Within hours, the PC was recovered.