"The suspects in the murder of subject Khashoggi committed the crime deliberately," Prosecutor General Saud Mujib said in a statement, aired by the broadcaster.
Earlier in the day, Turkish Foreign Minister Mevlut Cavusoglu stated that Ankara would not launch an international investigation into the Khashoggi case, adding, however, that Turkey had shared information on the issue with some parties.
"Attorney General: Suspects in the Khashoggi case did it with premeditated intent," the tweet says.
Jamal Khashoggi was a columnist for The Washington Post and a prominent critic of Saudi policies. On October, 2 he entered the Saudi Consulate in Istanbul in order to obtain documents for his marriage and has not been seen since.
Saudi Arabia initially denied reports that Khashoggi had been abducted or murdered in the consulate, but on October 19, Riyadh admitted that the journalist had been killed during a fight inside the diplomatic facility.