U.S. Secretary of State Mike Pompeo met with Saudi Arabia's King Salman and Crown Prince Mohammed bin Salman on Tuesday about the missing Saudi journalist last seen two weeks ago entering Riyadh's consulate in Istanbul. Pompeo also was to meet with Saudi Crown Prince Mohammed bin Salman, whom Khashoggi wrote critically about for The Washington Post and whose rise to power prompted the writer to go into a self-imposed exile in the United States.
He had been critical of Prince Mohammed, who has cracked down on dissent with arrests.
Donald Trump had previously suggested "rogue killers" could be behind Mr Khashoggi's disappearance. And details - if they can be proven - like an autopsy expert identified by name, stepping off a private jet from Saudi Arabia, carrying a bone saw to perform an "interrogation", may prove hard to explain away.
Earlier, a team of Saudi officials arrived in Istanbul for a joint investigation of the case with their Turkish counterparts. "It sounded like he, and also the Crown Prince, had no knowledge".
An expected search Tuesday of the consul general's residence did not take place, according to a deputy police officer near the building who spoke to CNN's team in Istanbul.
President Donald Trump suggested Monday that "rogue killers" could be responsible for the mysterious disappearance of Saudi journalist Jamal Khashoggi, an explanation offering US ally Saudi Arabia a possible path out of a global diplomatic firestorm.
Saudi officials have strongly denied any involvement in Khashoggi's disappearance and say that he left the consulate soon after arriving.
Meanwhile, the consul general himself, Mohammed Otaibi, left Turkey on Tuesday, the semiofficial Anadolu news agency said.
But late Monday evening - after Turkish authorities placed high iron barriers in front of the consulate - a motorcade of six cars drew up and Turkish police and prosecutors entered the premises.
"If the Embassy of Saudi Arabia claims that Khashoggi disappeared after leaving the embassy building, they must prove it", a message quoted President Recep Tayyip Erdogan as saying earlier. "I was on the floor every time defending Saudi Arabia because they're a good ally", said Graham. The Saudis, for two weeks, denied that he vanished inside their consulate, calling accusations that he was killed there, "lies and baseless allegations".
State Department spokeswoman Heather Nauert said Pompeo did not listen to a key piece of Turkey's evidence: an audio tape that Turkey claims captures Khashoggi's struggle and death inside the consulate.
US officials began predicting over the weekend, however, that the Saudis would inevitably admit complicity in the death of Khashoggi and claim a "botched operation", said one person familiar with the discussions.
Iran, as the regional rival to Saudi Arabia, would be the prime beneficiary if the Saudis were to lose their defensive U.S. umbrella.
Trump has threatened the kingdom with "severe punishment" if it is shown that Khashoggi was killed inside its Istanbul mission.
Speaking to the Fox Business Network on Wednesday, Trump again cited counterterrorism cooperation with Saudi Arabia and the kingdom's contracts with USA defense contractors.
"My assessment from these meetings is that there is serious commitment to determine all the facts and ensure accountability, including accountability for Saudi Arabia's senior leaders or senior officials", Pompeo said Tuesday after meeting.
"I'm not giving cover at all", Trump added, referring to Saudi Arabia.