Turkish officials said they shared evidence in recent days, including the details of an audio recording, with both the U.S. and Saudi Arabia to support their conclusion that Mr. Khashoggi was killed at the hand of Saudi operatives. It wasn’t clear how Turkish officials had an audio recording.

The recording indicates how Mr. Khashoggi was killed in the office of the Saudi consul general, Mohammad al-Otaibi, minutes after he walked into the consulate building on Oct. 2, said people familiar with the matter. Mr. Khashoggi wasn’t interrogated, the people said. Instead, he was beaten up, drugged and killed by Saudi operatives who had flown in from Riyadh earlier in the day, the people said.

Then, on the recording, a voice can be heard inviting the consul to leave the room, the people familiar with the matter said. The voice of a man Turkish authorities identified as Saudi forensic specialist Salah Al Tabiqi can be heard recommending other people present to listen to some music while he dismembered Mr. Khashoggi’s body, the people said.