"We continue to work diligently to ascertain all facts about this murder. We are going to hold accountable not only those who executed the murder but also those who led, involved or were connected to it," Palladino said.
Following more than two weeks of denials, Saudi Arabia admitted on October 19 that Khashoggi had been killed in a brawl inside the consulate in Istanbul. According to Riyadh, 18 people have been arrested over their suspected involvement in the incident and the country's deputy intelligence chief has been fired.
Khashoggi, a US resident and columnist for The Washington Post, was last seen entering the Saudi consulate in Istanbul on October 2.
On Wednesday, the Istanbul prosecutor's office said in a statement that Khashoggi's body was dismembered and destroyed after he was strangled in the Saudi Arabia's consulate in Istanbul.