“We have to get an outcome from this investigation as soon as possible. The consulate officials cannot save themselves by simply saying ‘he has left’,” Erdogan told a news conference in Budapest on Monday.
“The relevant authorities are obligated to provide proof of this claim, on this matter. If he left, you must prove this, you will prove this, even if it’s with visuals. Those who ask Turkish authorities ‘where is he?’ should first be asking ‘how did this happen?'” Erdogan added.
“Turkish Airlines or (other) airport arrivals and departures are all being investigated. With these departures and arrivals there were certain people who came from Saudi Arabia.
“The chief prosecutor’s office is working on it, investigating, doing everything. And we have said – especially to all our relevant agencies, our security forces, our intelligence agency, all of them, the foreign ministry – ‘work together’ and we’ll see the reports our prosecution prepares.”
Khashoggi disappeared after entering the Saudi consulate on October 2 to sort out paperwork and Turkish sources told Reuters news agency on Saturday they believed he was killed inside the building in what they described as a “premeditated murder”.
Erdogan, who said he was personally following the case, added that Turkey had no documents or evidence at hand regarding the case.
Turkey has formally requested access to the Saudi consulate for a full forensic search of the premises.
Earlier on Monday, officials in Istanbul told Al Jazeera they “expect [Saudi Arabia’s] full cooperation during the investigation” into the fate of the missing journalist.
On Sunday, Turkish Deputy Minister of Foreign Affairs Sedat Onal summoned the Saudi ambassador to Turkey to the foreign ministry for a second time since Khashoggi’s disappearance, sources at the ministry told Al Jazeera.
An unnamed source inside the consulate was quoted by the official Saudi Press Agency as denying the claims, saying the accusations were “baseless”.
A leading critic of the Saudi government’s reform programme under the stewardship of Crown Prince Mohammed bin Salman, Khashoggi had been living in self-imposed exile in the United States for over a year.
Speaking on Al Jazeera’s UpFront earlier this year, Khashoggi said that there was no space for debate in Saudi Arabia with intellectuals and journalists jailed for questioning policies.
“As we speak today, there [are] Saudi intellectuals and journalists jailed. Now, nobody will dare to speak and criticise the reforms [initiated by the crown prince],” he said, adding that “it would be much better for him to allow a breathing space for critics, for Saudi intellectuals, Saudi writers, Saudi media to debate”.
Asked whether Saudi Arabia could ever become democratic under bin Salman, Khashoggi said: “Not on his watch. I haven’t heard him make even the slightest inference that he would open the country for power-sharing, for democracy.”
In his writings for the Washington Post, the Saudi commentator criticised Saudi policies towards Qatar and Canada, the war in Yemen and the crackdown on dissent and the media in the kingdom.