Russian President Vladimir Putin has vowed to "do everything so that the organizations and perpetrators of the vile and cynical" murder of opposition leader Boris Nemtsov are brought to justice.
The message from a telegram Putin reportedly sent to Nemtsov's mother was posted on the Kremlin's official website on February 28.
The telegram expressed condolences and praised Nemtsov for having left his mark on the history of Russia.
The message continued that Nemtsov occupied important posts for Russia during a difficult transitional period and that he honestly stated his position and fought for his point of view.
Nemtsov was a leading critic of Putin and the Russian government's policies and told the Sobesednik news website earlier this month he feared for his own life.
"I'm afraid Putin will kill me," Nemtsov said on February 10.
Nemtsov also quoted his mother as having told him, "When will you stop scolding Putin? He will kill you!"
Fellow opposition leader Aleksei Navalny, who remains under house arrest, joined the chorus of observers asserting that -- particularly ahead of the opposition demonstration planned for March 1 -- Russian intelligence services would have had Nemtsov under surveillance at the time of the shooting.
Russian Prime Minister Dmitry Medvedev said he was "shocked by the cruel, cynical murder of Boris Efimovich Nemtsov," adding that it was "a personal tragedy for his relatives and friends...[and] a great loss for our society, whose freedoms and interests he always defended."
Based on reporting by TASS and Interfax