The Saudi heir and his friends in the White House evidently calculated that the outcry over the barbarous murder of Jamal Khashoggi would die out over time, and that Crown Prince Mohammed bin Salman would be free to continue on his autocratic way, repressing critics and dissidents with impunity. They were wrong.

More than four months have passed since Mr. Khashoggi was savagely throttled and dismemberedin the Saudi Consulate in Istanbul and then discarded, but the bald lies told by the Saudi government to protect the prince — including the attempt to pin the murder on 11 anonymous Saudis, of whom five are said to face execution — and the cynical argument by President Trump that Saudi largesse is more important than justice, have only intensified demands for a full reckoning.

The latest have come from American intelligence agencies, a United Nations investigator and a coalition of nongovernmental organizations, sources that in their diversity and breadth should serve notice on Prince Mohammed that all his oil wealth and powerful friends will not wash away the blood of the slain journalist.

A report in The Times on Thursday said the National Security Agency and other American spy agencies have uncovered an intercepted conversation in which Prince Mohammed tells a top aide more than a year before Mr. Khashoggi’s murder that if the self-exiled journalist cannot be enticed back to Saudi Arabia, he should be brought back by force. And if that didn’t work, the prince is heard to say, he would go after Mr. Khashoggi “with a bullet.”

Whether Prince Mohammed meant that literally or figuratively, the quote reveals a young, ruthlessly ambitious autocrat furious that a one-time insider dared criticize him as he sought to impose his will on the kingdom, including the repression of all who dare speak their mind. It was shortly after that conversation that Mr. Khashoggi produced his first column for The Washington Post, where he wrote: “I have left my home, my family and my job, and I am raising my voice. To do otherwise would betray those who languish in prison.”

“We Saudis deserve better,” he concluded.

Despite Mr. Trump’s efforts to blunt the allegations against Prince Mohammed, who had cultivated a close relationship with the president and Jared Kushner, his son-in-law and senior adviser, an assessment by the Central Intelligence Agency weeks after the killing concluded that the crown prince had to have ordered it.

At the United Nations, the special rapporteur on extrajudicial executions, Agnes Callamard, reported Thursday that her initial findings “show prime facie case that Mr. Khashoggi was the victim of a brutal and premeditated killing, planned and perpetrated by officials of the state of Saudi Arabia.” Though that essentially confirmed what is already widely accepted, the very fact of the independent United Nations investigation under a respected human-rights expert (Ms. Callamard, of France, is also director of Columbia University’s Global Freedom of Expression project), whose team includes a British barrister and a Portuguese forensics expert, is a welcome escalation of the pressures on Saudi Arabia to come clean. The panel will report its full findings in June.

A coalition of prominent nongovernment organizations, meanwhile, issued a joint statement accusing the Saudi government of continuing to persecute dissidents, activists, journalists and independent clerics. The group — the Committee to Protect Journalists, Human Rights First, Human Rights Watch, Open Society Justice Initiative, PEN America and Reporters Without Borders — also accused the Trump administration of a “cover-up on behalf of the Saudi government” and called the trial of 11 Saudi individuals accused of killing Mr. Khashoggi “a sham.”