Jamal Khashoggi
Missing journalist Jamal KhashoggiANI

The New York Times has unearthed what is believed to be the strongest evidence yet for the direct involvement of Saudi Arabian Crown Prince Mohammed bin Salman (MBS) in the killing of dissident journalist Jamal Khashoggi.

According to the paper, secret audio tapes that recorded the sequence of events at the Saudi Consulate in Istanbul on October 2 reveals that a member of the kill squad told a superior 'Tell your boss' immediately after Khashoggi was killed.

The American intelligence establishment believes that boss refers to none other than MBS, NYT reported.

Earlier last month, a Turkish newspaper reported that Khashoggi had received a call from the prince after he was intercepted at the Saudi consulate in Istanbul on October 2. During the call, the prince had tried to convince Khashoggi to return to Riyadh, according to Yeni Safak.

The NYT report said that the crucial words are attributed to Maher Abdulaziz Mutreb, a member of the 15-memeber squad that flew to Istanbul to eliminate Khashoggi. Citing sources in the US intelligence, the report say Maher made the phone call and spoke in Arabic. It says "your boss" was a reference to Prince Mohammed, though his name was not taken.

It's also reported that the security officer, who often travelled with Prince Mohammed, told the man at the other end that "the deed was done," in obvious reference to the murder of Khashoggi.

"A phone call like that is about as close to a smoking gun as you are going to get ... It is pretty incriminating evidence," NYT quotes a former CIA officer as saying.

Meanwhile, Saudi Arabia denied on Monday the crown prince had any role in the killing.

The international uproar over the murder shook Riyadh, which had initially sought to dismiss it as an immaterial incident. But it was forced to first admit that the death was an accident, then say that rogue elements eliminated the dissident journalist. Riyadh changed its position several times, but finally offered a full probe. At all points the Saudis have categorically stated that neither MBS nor King Salman had any role in the killing of the journalist.

Though international pressure forced Saudi Arabia to admit that Khashoggi was killed at the consulate, Riyadh hasn't been able to offer any clue to what happened to his body.

Last week, in a heartbreaking interview with a news channel, Khashoggi's sons Salah and Abdullah appealed for the return of their father's body and said that they wanted to bury him with the rest of the family.

A week before that, leaks from high-ranking Turkish sources said Khashoggi's body was dissolved in acid. "We now see that it wasn't just cut up, they got rid of the body by dissolving it," a top aide to Turkish President Recep Tayyip Erdogan said.

How Mohammed bin Salman is revolutionizing Saudi Arabia

Meanwhile, reports emerged last week that another dissident journalist was killed in detention in Saudi Arabia. Journalist Turki bin Abdulaziz al-Jasser was bumped off in prison after Saudi intelligence came to the conclusion that he had administered the Twitter account Kashkool, which had exposed human rights violations perpetrated by the top members of the royal family.