Ukrainian president Petro Poroshenko said on Saturday Russian opposition politician Boris Nemtsov was murdered because he planned to disclose evidence of Russia's involvement in Ukraine's separatist conflict.
Mr Poroshenko paid tribute to Mr Nemtsov, who was shot dead late on Friday, and said the fierce critic of president Vladimir Putin had told him a couple of weeks ago that he had poof of Russia's role in the Ukraine crisis and would reveal it.
“He said he would reveal persuasive evidence of the involvement of Russian armed forces in Ukraine. Someone was very afraid of this ... They killed him,” Mr Poroshenko said in televised comments during a visit to the city of Vinnytsia.
More than 5,600 people have been killed since pro-Russian separatists rebelled in east Ukraine last April, after the ousting of a Moscow-backed president in Kiev and Russia’s annexation of the Crimea peninsula.
Kiev and its Western allies say the rebels are funded and armed by Moscow, and backed by Russian military units. Moscow denies aiding sympathisers in Ukraine, and says heavily armed Russian-speaking troops operating without insignia there are not its men.
Russia's Investigative Committee is pursuing several lines of inquiry following the murder, including the possibility it was an attempt to destabilise the political situation, Interfax news agency said.
It said the committee, which answers to president Vladimir Putin, also saw an attack by radical Islamists as a possibility in the case and that there could be links with events in Ukraine.
Mr Nemtsov (55), an outspoken critic of Mr Putin and Russia’s role in the Ukraine crisis, was shot dead steps from the Kremlin in a murder that underscored the risks taken by the Russian opposition.
He was shot four times in the back by assailants in a white car as he walked across a bridge over the Moskva River in central Moscow with a Ukrainian woman, who was unhurt, just before midnight on Friday, police said.
Police sealed off the blood-stained bridge close to the red walls of the Kremlin and Red Square for two hours after the gangland-style killing reminiscent of Russia in the chaotic 1990s after the collapse of the Communist Soviet Union.
A former deputy prime minister who had feared he would be murdered, Mr Nemtsov was the most prominent opposition figure killed in Mr Putin’s 15-year-rule. The Kremlin deflected blame and the government said everything must be done to find the killers.
Mr Putin condemned the “brutal” slaying and took the investigation under presidential control, saying it could have been a contract killing and a “provocation” on the eve of a big opposition protest Mr Nemtsov had been due to lead on Sunday.
Agencies