In a town where the lovestruck can select from a roster of Elvis lookalikes to marry them at 4am, what happened two weeks ago in Las Vegas was pretty strange, even by the locals' standards. Late on the morning of February 21 - nobody is precise about the exact time, location or identity of the first caller - someone rang a locksmith and complained that the remote-control locking system on the caller's car was refusing to respond. The old-fashioned key, linked to the same circuitry, wouldn't work either, so could the locksmith fix whatever had gone wrong? A couple of minutes later, another locksmith's phone rang. Different caller, different make of car, different security system, same problem. By the end of the day, the best estimate is that police, fire brigade, locksmiths, car dealerships and tow-truck services had received at least 200 calls from stranded motorists. Many who are still puzzling over the February 21 incident put the figure as high as 1000. "Maybe it's those little green men," joked Mike Estrada, a spokesman for the United States Air Force's Nellis Air Base, which sprawls over 4100 square kilometres of desert 160km north of Vegas. He was referring to the Area 51 military research facility, which sits in the middle of Nellis' bombing range and where UFO buffs and conspiracy theorists maintain the Pentagon picks apart space aliens and their crashed flying saucers. While no one seriously blames intergalactic vandals for the lockouts, the general belief in Vegas is that Estrada, whose own car also was locked tight, might have been pointing reporters in the right direction. The likely culprit, say some, was a top-secret test of equipment intended to fry an enemy's circuitry.