If the Turks have the video, it is likely that the room that was used is known. It is difficult to get rid of all DNA.
Saudi denials and deflection of any knowledge of Khashoggis whereabouts read from a Kremlin playbook, as does his alleged death.
Turkey, meanwhile the worlds most prolific jailer of journalists now finds itself in the peculiar position of being a champion for a columnist who vanished under its nose.
https://www.theguardian.com/world/2018/oct/07/khashoggi-case-against-saudi-agents-reverberates-through-ankara-and-riyadh