Turkey says that Jamal Khashoggi was murdered inside Salafi Arabia's consulate in Istanbul.

Neither of those states is known for its respect for human rights, or for honesty. There is no hard evidence. However, if Salafi Arabia cannot produce Khashoggi alive, we will have to consider the accusation proved.

It would not surprise me for Salafi Arabia to assassinate dissidents, given that it has sentenced dissidents to death. It does surprise me that it would do so in a way that is implausible to deny and would cause a diplomatic incident.