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

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

Starting in the 1990s, Kelley, then a CIA officer, was falsely accused by his own agency, as well as by the FBI, of supplying covert information to Moscow.

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

Reinstated by the CIA in 2001, Kelley retired in 2006.

During his ordeal, 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.

Brian Joseph Kelley was born on Jan. 8, 1943, in Waterbury, Conn. He earned a bachelor’s degree in political science from St. Michael’s College in Colchester, Vt., followed by a master’s in East Asian studies from Florida State University.

From the mid-1960s to the mid-1980s, Kelley served in the Air Force, working in its Office of Special Investigations. Afterward, he joined the CIA, where he worked in classified counterintelligence.

In a telephone interview Wednesday, David Wise, the author of “Spy: The Inside Story of How the FBI’s Robert Hanssen Betrayed America” (2002), said that Kelley’s troubles took root in the late 1980s, after he discovered information that led the FBI to start investigating a State Department official, Felix Bloch, as a possible spy for Moscow.

After someone alerted Bloch to the investigation, suspicion fell on Kelley.

“In the wilderness of mirrors of counterintelligence, the idea that he was instrumental in discovering Bloch made him a suspect of having tipped off Bloch,” Wise said.

In fact, the tip had come from Hanssen.

As best as Kelley could determine afterward, his wife said, he was followed around the clock for several years. His phone was tapped, he was subject to rigorous interrogation and his family and colleagues were questioned.

Appearing on the CBS News program “60 Minutes” in 2003, Kelley’s lawyer, John Moustakas, said, “They threatened him with capital offenses,” adding, “His sisters, his daughter, his friends, his colleagues were all told, to the exclusion of all others, ‘Brian Kelley is an agent of the Russian government.’”

Kelley was suspended from his job for more than a year.

In 2000, the FBI paid $7 million for a secret KGB file that contained an audiotape of the U.S. mole talking to his Russian handler. Agents played it, expecting to hear Kelley’s voice. But the voice they heard was Hanssen’s.

Arrested in 2001, Hanssen pleaded guilty and is serving a life sentence at the so-called Supermax federal prison in Florence, Colo.

Bloch, who was not charged, was dismissed from the State Department in 1990 and has since worked as a grocery clerk and a bus driver in North Carolina.

Kelley eventually received apologies from both the FBI and the CIA. In 2007, the year after he retired, the CIA awarded him its Distinguished Career Intelligence Medal.