The CIA has closed the book on the mysterious case of the upside-down stamps.

Four years after nine Central Intelligence Agency employees profited from the discovery of one of the biggest stamp errors in U.S. history, the agency yesterday disclosed it had fired four of the workers and disciplined the others for taking the misprinted stamps from agency supplies and selling them to a stamp dealer for thousands of dollars.

CIA Director William H. Webster, following a lengthy investigation and internal appeals, decided that the workers had profited unfairly from their government positions and ordered the personnel actions. He directed that four of the stamps, which four workers returned to the agency, be donated to the Smithsonian Institution.

The four workers who were fired had refused to return the stamps, which are currently valued at about $17,000 each. One employee told the CIA he lost his stamp, and the agency believes the worker, a spokesman said.

"This case is important to every employee in the agency because it gives a clearer picture of what is expected of us," Webster said in an internal statement that was released yesterday. "Public service is a special trust. It is not easy; it is not without temptations."

The $1 stamps, which bear a drawing of an oil "rush lamp," are considered valuable because of a printing error at the Bureau of Engraving and Printing. Investigators say bureau crews inserted a partially printed sheet of 400 stamps into a press upside down. The sheets carried the image of a red and yellow glowing flame, which did not match up with the base of the lamp and the stamp's lettering.

The error went undetected at the bureau and at the U.S. Postal Service, and the CIA purchased 95 of the misprints at a McLean post office for use on agency mail.

The nine accused CIA workers, who were not identified, sold 85 of the misprinted stamps to a New Jersey stamp dealer for an undisclosed price in April 1986. The workers gave the dealer an 86th stamp, which was torn, and they each kept one of the misprinted stamps, according to investigators.

Until 1987, when the bureau released copies of its report on the misprinting, the CIA's role in the stamp error was not known. Stamp dealers had said the stamps were discovered by a group of workers at a "business" in Northern Virginia who wished to remain unidentified.

"In resolving the stamp case," Webster said in his May 10 decision, "this organization has determined that personal gain is to be achieved through work and not through appropriating government property."

"It also has determined that those who make errors in judgment can be offered another chance," he said, referring to the five workers who acknowledged their participation in the stamp scheme.

The four discharged workers were dismissed for lying to agency investigators and converting government property to private use, said CIA spokesman Peter Earnest.

The CIA's acknowledgments came shortly after Smithsonian officials confirmed they had received the four stamps from the CIA with a letter of transfer. The agency "in effect was giving them to the American people. They were government property," Earnest said.

"They are in wonderful shape . . . . It is a major rarity," said Jim Bruns, a curator at the Smithsonian's National Postage Stamp Collection, which previously had been given one of the misprinted stamps by a dealer.

Bruns said the stamp, which collectors call "the CIA invert," will gain greater value and recognition as more people learn the tale of how the error was discovered and changed the lives of workers at the intelligence agency.

As for the other 305 stamps, most stamp authorities believe they were sold to the public and used, unknowingly, on mail.