Five former Du Pont Co. employees threatened to sell secret documents on synthetic fibers to a competitor or begin production themselves if the chemical giant didn't pay them $10 million, authorities said.

Four of the five were arrested on extortion charges Monday in Switzerland in a hotel parking lot after they failed to meet with Du Pont officials and an undercover FBI agent where an exchange was to take place, said FBI agent Joseph V. Corless.Du Pont had planned to turn over a bogus $10 million check for the documents, which deal with the production of Lycra, the company's trade name for spandex fiber used in clothing such as swimming suits, leotards and pantyhose. The suspects also were to sign a contract agreeing not to produce spandex fiber for five years, Corless said.

The five had worked at the Du Pont plant in Mercedes, Argentina, one of several plants that make spandex. Du Pont was contacted about the documents in December.

Those arrested were Bruno Skerianz, age unknown; Raul A. Giordano, 36, operations supervisor for Lycra production; Antonio R. Inigo, 39, maintenance supervisor for Lycra production; and Maria I. Lorenzo de Bianchini, 39, secretary of the Lycra information office.