Brian J. Kelley, an American counterintelligence expert who helped focus attention on a possible Russian spy in Washington, only to be wrongly suspected of being a K.G.B. mole himself, died on Monday at his home in Vienna, Va. He was 68.

Mr. Kelley appeared to have died in his sleep, his wife, Patricia, said. The cause is not known.

Starting in the 1990s, Mr. Kelley, then a Central Intelligence Agency officer, was falsely accused by his own agency, as well as by the F.B.I., of supplying covert information to Moscow.

The real mole, the F.B.I. agent-turned-spy Robert P. Hanssen, was apprehended in 2001, but not before Mr. Kelley had been followed, interrogated, suspended and told that he might well be charged with a capital offense. Members of Mr. Kelley’s family were also interrogated, according to his wife and to news accounts.

Reinstated by the C.I.A. in 2001, Mr. Kelley retired in 2006.

During his ordeal, Mr. Kelley later told The Hartford Courant, he felt like the central character in “The Fugitive,” the 1993 film starring Harrison Ford as a man who becomes the target of a vast, organized dragnet after being falsely accused of murder.