Read more: Former Russian MP Voronenkov, key witness in Yanukovych treason case, assassinated in central Kyiv
Fugitive ex-MP
Voronenkov is a former Russian lawmaker of the Communist Party who left Russia for Ukraine in October 2016 together with his wife Maria Maksakova, opera singer and also a former Duma MP, representing Putin's Yedinaya Rossiya party.
"What would an open vote against result in for me? They said that I won't be able to walk 50 meters past the Duma. I would have jailed for imagined reasons, my family would have been destroyed," he claimed.After receiving Ukrainian citizenship in December 2016, Voronenkov backtracked on that claim, asserting that he wasn't in the voting hall and somebody else voted with his card in an interview to censor.net. In that interview, he also told that he left Russia because he no longer wanted to "live in lies and hypocrisy," and compared modern Russia to "Nazi Germany during Hitler’s rule," where "everyone knew he was killing the Jews but continued cooperating with him for many years, acting as if nothing was happening." Then he said that the annexation of Crimea was Russia's grave mistake. On 23 March, Ponomaryov told the Russian TV channel Dozhd that Voronenkov's coming to the Ukrainian side elicited mixed reactions even among the Russian opposition, and some opposition leaders called him a fraud. Ponomaryov himself said that Voronenkov is not a crook but
"a very dangerous person for the Russian corrupt law enforcement agencies, which made real investigations, had a lot of information about the smuggling business in Russia - and of course, he was a very valuable asset for Ukraine." "He feared for his life, so agreed to a state bodyguard - but as you can see, and it did not help," he stated.Ponomaryov also told that Voronenkov and Moksakova had a baby which would turn one in April, and they both had many plans. Ponomaryov wanted to create a center for investigating international corruption involving Russian special services and law enforcement, and his wife planned to sing at the Kyiv opera, with the first concert staged for late March.
Read also: Murder of Denis Voronenkov: what we know now
Witness in Yanukovych's treason case

"They testify that the Kremlin launched the mechanism of Russia's introduction of troops to the territory of Ukraine back in December [2013], when Euromaidan was still going on in the center of Kyiv. During the visit of [Putin's assistant] Surkov in December a possible military intervention was already discussed."At a press briefing after the murder, Lutsenko revealed that Voronenekov had already testified to the Ukrainian investigators that Yanukovych wrote not one but two letters asking for Russia to send troops to Ukraine. One was addressed to Russian President Vladimir Putin, and the other - to the Russian Duma.
"Kremlin execution-style murder"
Ukrainian officials were blunt in the accusations. President Petro Poroshenko called the murder an "act of state terrorism by Russia... done in the handwriting of the Russian special services." Ilya Ponomaryov is of the same opinion. At the joint press briefing with Lutsenko, he said that Moscow had first wanted to discredit Voronenkov so everybody in Ukraine would call him a fraudster. "When they understood that they won't fool anybody, they used the last argument," he said. Putin's press secretary Dmitry Peskov declined to comment on the murder of Voronenkov, calling the allegation of the Russian special services' involvement in the murder "absurd." Lutsenko informed that the Ukrainian Prosecutor's office was considering two motives behind the murder - that Voronenkov was killed due to being either a witness in the case on Yanukvoych's alleged treason, or an actor in an investigation about the FSB's involvement in smuggling operations under the cover of Vladimir Putin. A third option for the murder, as Tetyana Urbanska writes, would be to demonstrate to Ukraine and the world that those who know how the Kremlin works, who try to escape from Russia and speak publicly about the Russian repressive system, should be afraid, as they will not be safe anywhere. Such a demonstration of strengths indicates, according to her, that there are still many influential civil servants who would not mind giving their testimony against the "master," and that now there will be less of them. Voronenkov's assassination is not the first death of a key witness to Yanukovych's treason. On 20 February, Russia's permanent representative to the UN Vitaliy Churkin suddenly died in New York at the age of 64. According to materials of the Prosecutor General, Churkin was one of the main witnesses in this case. At a meeting of the UN Security Council he exhibited a letter Ukraine's ousted President wrote to Russian President Vladimir Putin asking him to deploy troops to Ukraine.
Read more: The Kremlin doesn’t know what to do with Yanukovych’s letter