Censor.NET reports referring to an article in The New York Times.
The article says the killing coincided with a fire and explosion at a gigantic Ukrainian army ammunition depot in the country's east that the authorities blamed on Russia.
Ukraine's president Poroshenko said it was "no accident" that the killing of the lawmaker Voronenkov occurred at the same time as the ammunition depot explosion and blamed the Russian government for "an act of state terrorism."
Voronenkov was member of the Russian Parliament before defecting to Ukraine last year with his wife, saying they were escaping political prosecution.
In his statement, Poroshenko called Voronenkov "one of the main witnesses of Russian aggression against Ukraine."
According to The New York Times, the killing in Kyiv was unusually bloody and chaotic in comparison with other contract murders being a common occurrence in former Soviet countries.
The article also stresses that contract killings in Russia are often carried out with a theatrical flourish or significant timing, to amplify the message.
"When the Russian opposition leader Boris Y. Nemtsov was shot to death in 2015, his body fell on the sidewalk of a bridge with the red brick walls of the Kremlin and St. Basil's Cathedral, symbols of the Russian state, as a backdrop," it says.
Denys Voronenkov was shot dead in downtown Kyiv March 23. The killer also managed to injure Voronenkov's bodyguard. The incident took place outside Kyiv's Premier Palace Hotel.
Voronenkov was a witness in the treason case against fugitive Ukrainian president Viktor Yanukovych. In his recent interview with Censor.NET Voronenkov said that Yanukovych was a traitor "who was involved in mass slaughter, who had fled to the foreign country and urged foreign troops to slay his people. I believe this person should have received not asylum but a fair trial in Russia."
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