Longtime congressman from New York who spearheaded an inquiry in the 1970s into accusations that the intelligence establishment had abused its power. In 1975, he became chairman of the House Select Committee on Intelligence, which began examining suspicions that the Central Intelligence Agency had had its hand in coups in Chile and other countries and was spying on American citizens. The inquiry paralleled one in the Senate; they were the first in which Congress looked into allegations of abuse by the C.I.A. His parents died when he was still a small boy, and he was raised by relatives. He enrolled at Princeton University, then interrupted his studies to join the Marines. During World War II he was a fighter pilot in the Pacific, flying 120 missions. He completed his degree after his discharge. His first campaign for a House seat, in 1958, failed, but he was elected two years later, despite being a Democrat in a Republican district. Mr. Pike served for nine terms before choosing not to run for re-election in 1978. Mr. Pike’s first wife, Doris Orth, died in 1996, and a son, Robert, died in 2010. In addition to his daughter Lois Pike Eyre, he is survived by his second wife, Barbe Bonjour Pike; a son, Douglas; and two grandchildren.