Unnamed Turkish officials speaking to The Washington Post and Reuters on Saturday said that prominent Saudi journalist-turned-critic Jamal Khashoggi was killed in the Saudi Arabian Consulate in Istanbul this week.

The officials have so far provided no evidence or detail on how they arrived at this conclusion. CNN has not been able to independently confirm these reports and has not been able to get a comment from the Saudi government on the reports.

Khashoggi has been missing since he entered the consulate in Turkey's largest city on Tuesday, his fiancée and two other sources familiar with the event said.

Saudi Arabia has strenuously denied any involvement in his disappearance, calling the claims “false.” A Saudi official said Khashoggi exited the consulate shortly after he visited.

The Saudis did not, however, release any surveillance footage or other proof Khashoggi had left. Khashoggi's fiancée, who has not been named, tweeted Saturday “Jamal was not killed and I do not believe he was killed.”

She went with him to the consulate Tuesday but remained outside and never saw him emerge.

The Turkish government launched an investigation into the disappearance, according to Turkey's state-run news agency Anadolu.

“His whereabouts and who is responsible will be uncovered,” Omer Celik, spokesman for Turkey's ruling AK Party, said Saturday at a party meeting in Ankara, according to Anadolu.

Turkish police have reportedly examined surveillance footage from the area and said there is no sign of Khashoggi leaving the consulate, Turan Kislakci, the head of the Turkish Arab Media Association and a friend of Khashoggi's, told CNN.

Khashoggi, known in part for his interview with terror mastermind Osama bin Laden, was a Saudi royal court insider before he left Saudi Arabia in 2017 for Washington.

He began to contribute opinion pieces to The Washington Post that were critical of bin Salman's policies, including his consolidation of power.

He was named a contributing writer at the Post in January. Khashoggi said the Saudi government had ordered him to stop using Twitter after he wrote a tweet cautioning against the leadership's enthusiasm about Donald Trump, then the US president-elect.