The Turkish prosecutors have completed an investigation on the assassination of Russian Ambassador Andrei Karlov’s in December 2016, country’s state-run Anadolu news agency reported.

An indictment into the case is ready, and, if Ankara Prosecutor’s Office approves it, the case will be sent to the court, according to Anadolu Agency.

Karlov was shot dead by an off-duty Turkish police officer on Dec. 19, 2016, during a speech at a photo exhibition opening in Ankara. Security forces killed the attacker Mevlüt Mert Altıntaş right on the spot.

The Russian Foreign Ministry described the assassination as a terrorist act.

Turkish police arrested a total of eight people as part of the investigation, including four former police officers. Mustafa Timur Özkan, the organiser of the photo exhibition where Karlov was killed, and the head of the publishing group Guru Media, Hayreddin Aydınbaş, were also arrested on charges of involvement in the murder.

The killers of Karlov had links to Gülen Movement, which Turkey blames for masterminding a failed coup attempt in 2016, pro-government Sabah in 2017, quoted the Turkish prosecutors as saying.

Gülen movement denies any involvement in the coup attempt.