The U.S. State Department is looking into accusations that Saudi Arabia was involved in the alleged murder of Jamal Khashoggi, a prominent Saudi journalist who often criticized the Saudi royal family. Days after he vanished while visiting the Saudi Consulate in Istanbul, his friends feared the worst.

Turan Kislakci said Turkish officials told him Khashoggi was killed at the consulate, adding "his body was dismembered." Khashoggi's fiancee said he entered the Saudi Consulate Tuesday to get a marriage document and never came out.

The Washington Post on Saturday quoted two people with knowledge of Turkey's investigation as saying Turkey thinks he was killed in the consulate by a 15-member Saudi team sent "specifically for the murder." CBS News has not confirmed the Post report.

Saudi officials, however, said they have nothing to do with the journalist's disappearance, and even took a TV crew on a tour of the consulate to show he isn't there. Khashoggi is a high-profile Saudi dissident, living in self-imposed exile in the U.S. since last year.

In November 2017, he warned about what he called "one-man rule," referring to Saudi Arabia's newly appointed Crown Prince Mohammed bin Salman.

"I'm worried for my children," Khashoggi said at the time. "One man rule, as I said before, is bad. It always go wrong, in any country."

Khashoggi wrote for publications like the Guardian and the Post, which on Friday, left a blank space where his column should have appeared, along with the headline: "A missing voice."

Recep Tayyip Erdoğan, Turkey's president, says his country is studying surveillance footage taken at the consulate and airport. Mohammed bin Salman told Bloomberg News his country has "nothing to hide."