The security director of a Gaithersburg, Md., aerospace firm turned up after being missing for a week and said he was kidnaped, kept in the trunk of a car, then left in the Nevada desert. The FBI said the man later told authorities he made the story up because of job pressures.

Thomas Gehrts, 26, of Springfield, Va., told FBI agents and Las Vegas police late yesterday he left his car at an El Paso, Tex., shopping center and took a bus to Las Vegas where "he lost all his money and was kicked out," according to FBI spokesman Bill Jansen.

Jansen said Gehrts then went to Sunrise Mountain, on the outskirts of Las Vegas, and told occupants of a home that he had been wandering in the desert for two days after being dumped there by his abductors.

When questioned yesterday, Gehrts first told officers he was changing a tire on a lonely stretch of Interstate 10 between El Paso and the White Sands Missile Range in New Mexico when he was abducted by two men. He told officers the two men kept him in the trunk of their car for a week, allowing him only three meals. He said they dumped him in the desert Sunday and he wandered around for two days before stumbling on the home near Lake Mead.

Authorities said Gehrts has knowledge of classified defense and NASA information and works for Space Communications Co. of Gaithersburg, Jansen said Gehrts had been working at SCC's office in El Paso.

Gehrts was returned to El Paso today after further questioning. Jansen said Nevada officials planned no charges against the man.