Only a few weeks ago, it seemed as if the stun gun was a product whose time had come. The electrical self-defense device has become a big seller, both to worried citizens who dislike conventional guns and to police departments searching for a nonlethal method of "taking down" an emotionally disturbed suspect. "We can't keep 'em in stock," says Bobbi Repasy of the O'Herron police supply firm, which sells 250 a month in Danville, Ill.
Stun guns have been controversial since they were introduced ten years ago, however, and recent events have shown why. Five New York City police officers last...