Our International correspondent Borzou Daragahi explains everything we know about the case of missing journalist Jamal Khashoggi so far.
The Saudi writer vanished on 2 October while visiting the consulate to pick up paperwork he needed to get married.
Mr Khashoggi had written columns for the Washington Post that were critical of the Saudi crown prince.
Donald Trump said the Saudi heir to the throne "totally denied any knowledge of what took place in their Turkish Consulate".
He added that the crown prince "told me that he has already started, and will rapidly expand, a full and complete investigation into this matter. Answers will be forthcoming shortly".
US secretary of state Mike Pompeo has travelled to Saudi Arabia to talk to King Salman and the 33-year-old crown prince about the fate of the journalist.
It comes as a high-level Turkish official said police searching the Saudi consulate found evidence that Mr Khashoggi was killed there.
Authorities also appeared ready to search the nearby residence of the consul general after the diplomat left the country.