The murder of the opposition leader Boris Nemtsov was carried out by Zaur Dadayev, a former deputy commander of the Sever (North) Chechen battalion, a source in law enforcement authorities told Interfax.
"The results of forensic tests, obtained by law enforcement bodies, give reasons to believe that Dadayev was the man who shot Nemtsov," the source said. "However, this can only be asserted 100 percent when the murder weapon is found."
So far Dadayev has been reluctant to talk to investigators.
According to one of the theories investigators are pursuing regarding Nemtsov's murder is that it may have been motivated "by the politician's controversial remarks about Islam," the source said.
"At the same time, law enforcement authorities have identified foreign contacts of the Nemtsov murder suspects, so a theory about a foreign trail is also being actively investigated," the source said.