Saudi Arabia's top prosecutor, Saud al-Mojeb, met with Istanbul's chief public prosecutor, Irfan Fidan, for an hour and 15 minutes at Istanbul's main courthouse, Turkey's state-run Anadolu news agency said.
The two countries have announced a joint investigation of the journalist's killing in Saudi Arabia's consulate in Istanbul, although Turkey has leaked evidence to the media in an apparent effort to pressure its regional rival over the crime committed by Saudi officials.
Turkey alleges a hit squad from Saudi Arabia traveled to Istanbul to kill the journalist who was critical of the Saudi leadership and then tried to cover it up. Under mounting international pressure, Saudi Arabia has changed its narrative about Khashoggi's killing several times, only recently acknowledging that Turkish evidence shows it was premeditated.
Turkey says a trial in Turkey would be transparent, reflecting concerns about Saudi attempts to dodge responsibility for the killing. Turkey's foreign minister, Mevlut Cavusoglu, on Monday welcomed the cooperation between Turkish and Saudi investigators and said he hoped there would be no further delays.
"The investigation should be concluded as soon as possible," Cavusoglu said. "The whole world is curious. All the truth should be revealed." Turkey has been pushing Saudi Arabia to help locate Khashoggi's body, which has not been found.
Turkey is seeking the extradition of the Saudi suspects detained for the killing, which happened after Khashoggi entered the consulate on Oct. 2. Saudi Foreign Minister Adel al-Jubeir, however, says the kingdom will try the perpetrators and bring them to justice after the investigation is completed.
Saudi officials characterize the killing as a rogue operation carried out by Saudi agents who exceeded their authority. Yet some of those implicated in the killing are close to Crown Prince Mohammed bin Salman, the kingdom's heir-apparent whose condemnation of the killing has failed to ease suspicions that he was involved.
Khashoggi, a onetime Saudi insider and U.S. resident who lived in self-imposed exile for almost a year before his death, had written critically of the crown prince in columns for The Washington Post. Al-Mojeb, the prosecutor visiting Istanbul, was named attorney general by Saudi King Salman last year after a palace shakeup that saw Prince Mohammed sideline his elder, more experienced cousin, Mohammed bin Nayef, for the title of crown prince.
Months later, al-Mojeb played a key role when high-level Saudi princes, businessmen, government officials and military officers were detained and stripped of significant sums of their wealth in exchange for freedom. The sweep, described by Prince Mohammed bin Salman and his backers as an anti-corruption drive, helped the new crown prince consolidate his power and weaken potential rivals.
Turkish President Recep Tayyip Erdogan says his country will reveal more evidence about the killing but is not in any rush to do so. U.S. Defense Secretary Jim Mattis has said the killing undermines regional stability and has urged Saudi Arabia to conduct a full and complete investigation.
In a video released Monday, journalists from a number of media organizations read extracts from Khashoggi's last Washington Post column, titled "What the Arab world needs most is free expression." "We will continue to campaign for truth and accountability for his horrific murder, by those who planned, ordered and executed it," said Kumi Naidoo, secretary general of Amnesty International, which released the video.