Heartbeat detector is big in Japan.

• Position: Security beat: homeland defense briefs

Despite less than glowing reviews from U.S. research labs, the Japanese regional police force has purchased 100 passive detectors that purport to detect the electric field created by a beating human heart.

"Everyone looked at us like we were loonies," Howard Sidman, president of DKL International Inc., told National Defense.

The product, called LifeGuard, claims to detect unique ultra low frequency fields generated by the heartbeat, so that living humans can be found, company officials said. The technology is touted as being able to locate a standing adult from a distance of 500 meters in the open, and at shorter distances through concrete walls, steel bulkheads, heavy foliage or water.

Skeptics have called the device no better than a dowsing stick, and during 1998 trials at Sandia National Labs the...