Doctors have conducted a mental and psychiatric evaluation of Zaur Dadayev, the suspected murderer of politician Boris Nemtsov; he will be ruled fit to stand trial, his defense lawyer said.

"My client underwent the evaluation on an outpatient basis. So far the results are unknown, everything will depend on when investigators wish to make them available to us," the defense lawyer, Shamsudin Tsakayev, told Interfax on Monday.

"I think he will be found mentally fit," he added.

Dadayev was examined at the Alexeyev Psychiatric Clinic Hospital N1, his lawyer said. "He did not refuse from it and responded to all questions from doctors. Everything went according to a standard procedure, a 'standard conveyor' of a sort," the defense lawyer said.

Nemtsov was shot dead on Bolshoi Moskvoretsky Bridge in Moscow on February 27, 2015. The murder is being probed under Article 105 (homicide) and Article 222 (unlawful weapon possession) of the Russian Criminal Code. The inquiry is conducted by the Main Investigative Directorate of the Russian Investigative Committee.

Five suspects have been detained in connection with the case until August 28 (under the Basmanny District Court orders): the two suspected perpetrators Dadayev and Anzor Gubashev; and their suspected abettors Khamzat Bakhayev, Shadid Gubashev and Temerlan Eskerkhanov.

On July 8, a source familiar with the situation told Interfax that all five would be evaluated concerning their mental health.