WASHINGTON — Jack Valenti, who was riding six cars back in President Kennedy's motorcade, didn't hear the gunfire.

But when the car in front of him suddenly sped off, he knew something was wrong.

"Sometimes the brain does not want to answer questions that the mind doesn't want to hear," said Valenti, who had convinced himself that the president was simply late for his speech at the Dallas Trade Mart.

Upon arriving there, Valenti discovered "about 2,000 people, with no president." He went to find out what was happening, and the next thing he knew, he was being escorted to a hospital by a sheriff's deputy.

"I went to the basement. There was a stainless steel door that later on I was told was the emergency operating room, where the lifeless body of Kennedy was already there, though we didn't know it," Valenti said. "It was a lot of people down there, somber and grief-stricken, and absolutely full of wonderment."

Vice President Lyndon Johnson's chief aide told Valenti that Johnson wanted to talk to him.

"Then he hesitated, and he leaned down close to my ear, and he said, 'The president is dead, you know,"' Valenti recalled. "The tears just came, just awful. He said, 'Compose yourself,' and we went to this room where Johnson had been sequestered."

Valenti called Nov. 22, 1963, a day "that will live in perfidy." He described it poignantly Wednesday in an interview with The Associated Press.

Even 40 years later, he recalls the assassination in Dallas in vivid detail, from Johnson's impromptu request that Valenti, at that time a political consultant, join his administration, to Jackie Kennedy's refusal to change her bloodstained blouse, to Valenti's first assignment from Johnson: to track down the wording of the oath of office so Johnson could be sworn in as president aboard Air Force One.

"It is so seared in my memory I literally, sometimes at night — not often, but once or twice a year — I relive that day," Valenti said. "Because it was an apocalyptic intrusion. I think the nation's life changed, and I can assure you mine radically changed."

Johnson made two decisions instantly, Valenti said: He refused to let Air Force One take him back to Washington without Kennedy's body on board, and insisted on taking the oath of office on the plane. A deputy attorney general assured Johnson he already was president, but Johnson took the oath there anyway, swearing on a Catholic missal found in the presidential bedroom aboard Air Force One, Valenti said.