Correction: An earlier version of this story incorrectly described the location of Mr. Pike’s hometown of Riverhead, N.Y. It is not on the northern shore of Long Island but at a point on Great Peconic Bay between the northern and southern coasts.

Mr. Pike pats the classified material on the 1973 Arab-Israeli war that the White House turned over to the House Intelligence Committee on September 10, 1975. (James K. W. Atherton/The Washington Post)

Otis G. Pike, a nine-term New York congressman who was a persistent critic of Pentagon overspending and led one of the first congressional investigations of abuses by U.S. intelligence agencies, died Jan. 20 at a hospice in Vero Beach, Fla. He was 92.

His daughter, Lois Pike Eyre, confirmed the death and said she did not yet know the cause.

Mr. Pike, who was elected to the House of Representatives in 1960, was regarded as an independent-minded maverick during his 18 years in Congress. He was a Democrat elected from a Republican-leaning district on Long Island, a Marine Corps veteran who was skeptical of Vietnam War escalation, and a patrician, bow-tied lawyer with a wicked sense of humor, which he used to ridicule wasteful spending.

In 1973, Mr. Pike was credited with single-handedly grounding a $14 million program that awarded extra pay for flight duty to generals and admirals who never piloted anything more aerodynamic than a desk at the Pentagon.

Standing on the floor of the House with his arms outstretched like a plane in flight, Mr. Pike used mockery to plead his case.

“If the in-basket is continually loaded on the starboard, or right-hand, side of the desk, and the out-basket is continually empty on the port, or left-hand, side of the desk,” said Mr. Pike, who flew 120 missions as a Marine pilot in World War II, “wood fatigue sets in, the landing gear tends to buckle and the whole fuselage crashes down on your feet.”

As the chamber echoed with laughter, the flight-pay policy was abolished.

Mr. Pike had his most conspicuous moment in the public eye in 1975, after revelations of the CIA’s “family jewels” — suspected involvement in clandestine operations that may have included killings and coups overseas and spying on U.S. citizens.

In July 1975, he became chairman of a committee that was the House counterpart of a Senate committee led by Sen. Frank Church (D-Idaho). Both panels reviewed activities of the CIA and other intelligence agencies, marking the first time Congress had examined secret dealings and suspected abuses by the CIA since the spy agency’s founding in 1947.

During the often-testy hearings, Time magazine called Mr. Pike “the model of a properly pugnacious public servant — sharp-tongued and not easily intimidated.”

Mr. Pike challenged CIA Director William E. Colby to accept greater oversight of the CIA’s budget — then, as now, a secret, off-the-books appropriation. The CIA balked, saying the country’s intelligence operations could be hurt by opening its books.

Mr. Pike was alarmed by CIA excesses, including suspected involvement in efforts to oust leaders in Chile and other countries. After Secretary of State Henry A. Kissinger withheld certain documents and limited the number of State Department officials who could testify, the Pike Committee voted to hold him in contempt of Congress.

The contempt went both ways, as Kissinger charged the committee with acting “in a tendentious, misleading and totally irresponsible fashion.”

Among other findings, the Pike Committee called for central congressional oversight over intelligence operations, a prohibition of CIA-sponsored killings and more transparency in the intelligence budget.

“It took this investigation” into the CIA, Mr. Pike said in a 1976 New Republic interview with Italian journalist Oriana Fallaci, “to convince me that I had always been told lies [and] to make me realize that I was tired of being told lies.”

When Mr. Pike’s committee was scheduled to release its full report in January 1976, the full House of Representatives voted to keep it secret, citing national security concerns. A copy of the 338-page report was obtained by Daniel Schorr of CBS News and published by the Village Voice in New York.

Summoned to appear before a House committee, Schorr steadfastly refused to name the source of the leak and kept the secret until his death in 2010. Mr. Pike was adamant in conversations with his family and others, his son said, that he did not give the report to Schorr.

In the end, because the document was never officially released, Mr. Pike’s investigation was soon overshadowed by the Senate’s Church Committee, some of whose recommendations were adopted in measures to rein in the excesses of the CIA and other intelligence agencies.

Otis Grey Pike was born Aug. 31, 1921, in Riverhead, N.Y., a town on Long Island then known for its potato farms and fishing fleet. He was an orphan by 6 and was raised by two older sisters and an aunt.

One of his sisters was a social worker during the Depression and told Mr. Pike about a local farm family.

“All they had for Sunday dinner was boiled potatoes,” he recalled in a 1967 interview with the New Yorker magazine. “I was surprised that in a great country like America such a thing could happen. All my family had always been Republicans, but that kind of thing, and what Franklin Roosevelt tried to do about it, turned me into a Democrat.”

Mr. Pike graduated from Princeton University in 1946 and from Columbia University law school in 1948.

He practiced law in his home town, was elected justice of the peace and served on his town council. After losing his first congressional bid in 1958, Mr. Pike defeated the Republican incumbent, Stuyvesant Wainwright II, two years later. He went on to hold seats on the Armed Services and Ways and Means committees.

Mr. Pike enjoyed singing and playing the piano and ukulele. By the time he decided not to seek reelection in 1978, he lamented to The Washington Post that Congress was no longer much fun and had become dominated by “two kinds of people — millionaires and Boy Scouts.”

After his congressional career, he wrote a column on public affairs for Newsday and the Newhouse News Service until 1999. He retired to Vero Beach.

His first wife, Doris Orth Pike, died in 1996 after 50 years of marriage. A son, Robert Pike, died in 2010.

Survivors include his wife of 10 years, Barbe Bonjour Pike of Vero Beach; two children from his first marriage, Lois Pike Eyre of Riverhead and Douglas Pike of Paoli, Pa.; and two grandchildren.

While speaking out against what he considered outlandish defense spending during the Vietnam War, Mr. Pike cited the example of small metal rods with a retail cost of 50 cents. The Pentagon, which bought them for $25.55 apiece, described them as “precision shafting.”

“For once,” Mr. Pike declared on the House floor, “the American taxpayer got precisely what he paid for.”