The crown prince, the next in line to the Saudi throne behind his ailing father, King Salman, has become the de facto ruler of Saudi Arabia and a close ally of the Trump White House – especially Jared Kushner, the President's son-in-law and senior adviser. The conversation appears to have been recently transcribed and analysed as part of an effort by intelligence agencies to find proof of who was responsible for Khashoggi's death. Journalist Jamal Khashoggi was killed in October. Credit:AP The National Security Agency and other US spy agencies are sifting through the years of the crown prince's voice and text communications that the NSA routinely intercepted and stored, much as the agency has long done for other top foreign officials, including close allies of the US. For the past several months, the NSA has circulated intelligence reports to other spy agencies, the White House and close foreign allies about the crown prince's communications. The reports were described by several current and former officials. Weeks after the killing, the CIA finished its first assessment about the operation, concluding that the crown prince had ordered it.

The conversation between the crown prince and the aide, Turki Aldakhil, took place in September 2017, as officials in the kingdom were growing increasingly alarmed about Khashoggi's criticisms of the Saudi government. That same month, Khashoggi began writing opinion columns for The Washington Post, and top Saudi officials discussed ways to lure him back to Saudi Arabia. Crown Prince Mohammed bin Salman. Credit:AP In the conversation, the crown prince said that if Khashoggi could not be enticed back to Saudi Arabia, then he should be returned by force. If neither of those methods worked, the crown prince said, then he would go after Khashoggi "with a bullet", according to the officials familiar with one of the intelligence reports, which was produced in early December. US intelligence analysts concluded that the crown prince might not have meant the phrase literally – in other words, he did not necessarily mean to have Khashoggi shot – but more likely used the phrase as a metaphor to emphasise that he had every intention of killing the journalist if he did not return to Saudi Arabia.

Days before the conversation with Aldakhil, according to the same intelligence report, the crown prince complained to another aide – Saud al-Qahtani – that Khashoggi had grown too influential. The crown prince said Khashoggi's articles and Twitter posts were tarnishing Mohammed's image as a forward-thinking reformer, and the criticism was more cutting because it was coming from a journalist who had once been seen as supportive of his agenda. Loading When al-Qahtani said that any move against Khashoggi was risky and could create an international uproar, his boss scolded him: Saudi Arabia should not care about international reaction to how it handles its own citizens, the crown prince told al-Qahtani. Crown Prince Mohammed also told al-Qahtani, according to an official who has read the report, that he "did not like half-measures – he never liked them and did not believe in them". Days after this conversation and the alleged one about the bullet, Khashoggi wrote his first column for The Washington Post: "Saudi Arabia Wasn't Always This Repressive. Now It's Unbearable." It was a withering attack on Crown Prince Mohammed's crackdown inside the kingdom.

"I have left my home, my family and my job, and I am raising my voice," Khashoggi wrote. "To do otherwise would betray those who languish in prison. I can speak when so many cannot." Spokesmen for the NSA and the CIA declined to comment. In a statement, Aldakhil said: "These allegations are categorically false. They appear to be a continuation of various efforts by different parties to connect His Royal Highness Crown Prince Mohammed bin Salman to this horrific crime. These efforts will prove futile." Officials at the Saudi embassy in Washington, contacted on Thursday morning, had not commented by 6pm, Washington time. US intelligence agencies have identified al-Qahtani as the ringleader of the operation that killed Khashoggi, and last year, he was put on a list of Saudi officials sanctioned by the United States for their role in the journalist's death. Al-Qahtani is viewed in the kingdom as a brutal enforcer of the crown prince's agenda and has used an army of online trolls to harass Saudi dissidents on social media. After Khashoggi's killing, the kingdom announced that al-Qahtani had been removed from his position as an adviser to the royal court. Saudi Arabia has since begun criminal proceedings against 11 people involved in the operation. Prosecutors are seeking the death penalty for five of them.

The kingdom has not released the names of the people on trial, and it is unclear whether al-Qahtani is among them. Loading Aldakhil, the other aide to the crown prince caught in the intercepts, until recently was the general manager of the Al-Arabiya television network in Saudi Arabia. He is an influential media figure in the kingdom and a prominent adviser to the crown prince. During the September 2017 conversation, according to intelligence reports, Aldakhil spoke to Crown Prince Mohammed about luring Khashoggi back to Saudi Arabia with the possibility of a job at Al-Arabiya. The crown prince was sceptical that Khashoggi would accept the offer. Last month, Aldakhil left his post at the network. Saudi news sites have reported that he is expected to be named the next Saudi ambassador to the United Arab Emirates.

US officials said there was no evidence that Aldakhil had knowledge of a specific plan to capture or kill Khashoggi, and his name had never been among the suspects in the killing. In the weeks after Khashoggi's death, classified evidence piled up that senior Saudi royals approved the Khashoggi operation, even as US officials insisted that there was no "smoking gun" directly tying the crown prince to it. The narrative from the Saudi royal court changed repeatedly, and the Saudi government has been determined to insulate the powerful crown prince from blame. Most recently, Saudi officials have said that the operation was a kidnapping gone awry – that the team had been sent to Istanbul to forcibly bring Khashoggi back to Saudi Arabia but made the decision to kill him after he refused to co-operate. Saudi officials have said that the crown prince had no knowledge of the operation. Loading Replay Replay video Play video Play video In the latest indication that the international uproar over Khashoggi's killing will continue, a UN investigator released a preliminary report on Thursday that concluded that Khashoggi "was the victim of a brutal and premeditated killing, planned and perpetrated by officials of the State of Saudi Arabia".

UN special rapporteur Agnes Callamard also said that Turkey's efforts to investigate the death of Khashoggi had been ''seriously curtailed and undermined by Saudi Arabia". The New York Times