Lyman B. Kirkpatrick Jr., 77, a former top CIA official, died Friday from complications of pneumonia at his home in Middleburg, Va. He entered the intelligence services when he enlisted in the Army in 1942, when he was on the editorial staff of U.S. News and World Report. He joined the CIA at its inception in 1947, eventually becoming its inspector general and then executive director, which at that time was the third-ranking position. He left in 1965 to teach at Brown University. As inspector general, he had the job of investigating some internal agency actions that were criticized years later -- among them the 1953 death of Frank Olson, an Army biochemist who died while using LSD in an agency experiment. Mr. Olson plunged to his death from the Hotel Statler in New York on Nov. 28, 1953. The CIA hid the truth about his death and his involvement in the drug experiment from his family until 1975, when it was disclosed in news reports.