Serge "Peter" Karlow, 84, a former CIA intelligence officer who won a decades-long campaign to clear his name after officials accused him of being a mole for the Soviets, died of pneumonia Nov. 3 at a hospital in Montclair, N.J. He lived in a nursing center in West Caldwell, N.J.

Mr. Karlow wrote about his ordeal in his 2001 memoir, "Targeted by the CIA: An Intelligence Professional Speaks Out on the Scandal That Turned the CIA Upside Down."

His once-promising career at the agency came to an abrupt end in the early 1960s when Anatoly M. Golitsin, then a recently defected KGB officer, told CIA officials that there had been an American mole stationed in Germany.

Golitsin said that although he didn't know the identity of the mole, he believed that the last name of the spy began with a "K." With those clues, the CIA narrowed its list of suspects to three people, including Mr. Karlow, who was described as a real-life counterpart to the fictional character Q, the master gadgeteer in the James Bond movies.

Mr. Karlow, who once had been stationed in West Germany, began his career during World War II with the CIA's predecessor, the Office of Strategic Services. The New York City native and Swarthmore College graduate also served in Algiers and Corsica. On a mission with naval intelligence, he lost his leg in an explosion off the coast of Italy when his PT boat triggered an acoustic mine.

In 1962, in an atmosphere of paranoia, Mr. Karlow found himself the central figure in the CIA's hunt for a mole.

Even though a four-month investigation failed to produce any evidence against him, Mr. Karlow was seen by many as a primary suspect. Isolated and shunned, he was forced to resign under a cloud of suspicion.

In 1963, he moved to St. Louis to join the international affairs office of the agricultural firm Monsanto Co. He transferred to the company's Washington office in 1970 and for a time was chairman of the Washington Export Council.

Dogged in his efforts to win a public exoneration, Mr. Karlow appealed to CIA directors William Casey and William H. Webster to reexamine his case. A CIA internal investigation opened in 1988 and found that the FBI had cleared Mr. Karlow years earlier.

In 1989, about 25 years after the allegations first were made, the CIA held a ceremony in which Mr. Karlow received an apology, a medal and financial compensation.

Mr. Karlow was active in the Association of Former Intelligence Officers in California and Florida, where he later lived.

His wife, Elizabeth Karlow, died in 1977.

Survivors include a son, James P. Karlow of Commerce Township, Mich.; a daughter, Alexandra Karlow Nolan of Montclair; a sister; and five grandsons.

Serge Karlow was cleared of accusations of being a mole.