"They are facing the final charges today. The investigators intend to bring the final charges today against Zaur Dadayev, Anzor Gubashev and Shadid Gubashev, Tamirlan Eskerkhanov and Khamzat Bakhayev over a contract murder committed by an organized group and illegal acquisition, carrying, transportation and storage of firearms (Article 105, part 2 and Article 222, part 3 of the Russian Criminal Code)," Markin said, TASS wrote.

Criminal proceedings against another accomplice — Beslan Shavanov, were dismissed in November 2015 on non-rehabilitating grounds in connection with his death as he blew himself up when police were trying to detain him in the Chechen capital Grozny.

The case against Ruslan Mukhudnov, who is the mastermind and organizer of the crimes and who is on the international wanted list since November, as well as other unidentified persons, will be considered in a separate procedure.

"In January 2016, investigators intend to complete the investigation within the main criminal case, and present the collected materials for examination to the injured persons and their representatives, and then — to the defendants and their lawyers", the Investigative Committee spokesman said.

"The implication of all the defendants in the crime is confirmed by the evidence collected within the criminal case, including the results of more than 70 complex forensic expert examinations, questioning of witnesses, face-to-face interrogations, examination of items and documents seized during searches in the defendants' residence places and protocols of examination of videos from surveillance cameras installed at the murder scene, as well as along the suspects' approach and escape routes," Markin said.

Co-chairman of the opposition party PARNAS Boris Nemtsov was gunned down in the center of Moscow in the evening on February 27.

Zaur Dadayev whom investigators consider the killer, Khamzat Bakhayev, Anzor Gubashev, Shadid Gubashev and Tamerlan Eskerkhanov were arrested over Nemtsov's murder. Later on, the Moscow City Court upheld the arrest in absentia of former officer of the North battalion Ruslan Mukhudinov, the suspected mastermind of the murder of Nemtsov.