"At year’s end the [Public Prosecutor's Office (PPO)] had not named the suspects nor the roles allegedly played by them in the killing, nor had they provided a detailed explanation of the direction and progress of the investigation", the report stated.
Last November, the Saudi PPO announced the indictment of 11 suspects in Khashoggi's murder, and later stated that 10 more individuals were under investigation.
READ MORE: US Talent Agency Reportedly Returns Saudis $400Mln Funds Due to Khashoggi Case
The State Department noted that in the past, Saudi Arabia did not punish officials accused of committing human rights abuses.
Many US lawmakers have said they believe that Saudi Crown Prince Mohammad bin Salman ordered the killing. The Saudi side, in turn, refuted these allegations, vowing to find and punish those responsible for the death of the journalist.