Despite nearly incontrovertible evidence — including grisly audio recordings described by Turkish officials of Mr. Khashoggi’s torture, murder and dismemberment — Mr. Trump insists he does not know what happened inside the Saudi consulate in Istanbul on Oct. 2 or who might have ordered it. And yet Mr. Trump almost certainly does know, if not from reading the newspapers then from the multiple intelligence agencies that report to him.

It stretches the imagination that Turkey has not shared these recordings with American intelligence agencies, and that they, in turn, would not have shared them with the president and Mr. Pompeo, a former director of the C.I.A. who discussed the killing with the Turkish president on Wednesday. Mr. Trump denied knowledge of any recordings (“if they exist,” he said Wednesday); Mr. Pompeo declined to comment.

The Turkish accounts have not been independently confirmed by Western journalists or American government officials. The latest information, which came out on Wednesday, was from an unidentified Turkish official who was said to have listened to the audio recording of Mr. Khashoggi’s last moments.

They were sickening. As soon as he entered the consulate, Mr. Khashoggi was seized by the Saudi agents who had flown in some hours earlier — including Salah al-Tubaigy, identified as the head of forensic evidence in the Saudi general security department. They began to cut off his fingers before murdering and dismembering him. As he worked, Dr. Tubaigy put on headphones, noting that “when I do this job, I listen to music,” and urged other members of the team to do likewise. When the consul-general, Mohammad al-Otaibi, protested — not to the violence, but “You will put me in trouble” — one of the agents replied, “If you want to live when you come back to Arabia, shut up.”

The Saudis have reportedly been searching for a cover story for the disappearance of the gadfly Saudi journalist, who had been living in self-imposed exile in the United States and writing columns for The Washington Post. Denial is no longer an option — Turkey appears to have solid evidence that Mr. Khashoggi was killed by thugs flown in from Saudi Arabia — so the word in Washington is that the Saudis will try to claim an attempted kidnapping or interrogation gone bad.