Russian journalist Arkady Babchenko wasn't killed on May 29.
Vasily Gritsak, head of the Ukrainian Security Service, told reporters that the agency faked Mr Babchenko's death to catch those who are trying to kill him.
Twitter users have expressed their utter disbelief after "murdered" Russian journalist Arkady Babchenko emerged alive and well at a press conference in Kiev, Ukraine, Wednesday. It was not immediately clear how exactly the murder was staged.
Babchenko was accused of lacking patriotism, something he called ironic considering he fought for his country in the first separatist war in Chechnya in the 1990s.
Mr Babchenko, 41, is one of Russia's best-known war reporters, but was forced to leave the country previous year because of repeated threats against him and his family. Ukrainian Prime Minister Volodymyr Groysman, in comments posted to his Facebook page, also implied involvement by Putin's government in Babchenko's death.
Kiev Police Chief Andrei Krishchenko told the press that "the first and most obvious" possible motive for the killing was Babchenko's work that's always been critical of the Russian president.More news: Cubs' Anthony Rizzo confident Pirates won't seek retribution for slide
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"This fashion of conducting global affairs is very sad", Russian Foreign Minister Sergei Lavrov was quoted as saying at a Moscow press conference on May 30.
A prominent Russian journalist and critic of President Vladimir Putin has been gunned down in Ukraine where he had fled into exile following threats, police say.
Police said that they had made one arrest in connection with the extraordinary operation.
Kiev has in recent years seen a number of deadly attacks on high-profile journalists and politicians. The Ukrainian police have launched a criminal investigation and said that two reasons could be behind the assassination, namely, the journalist's work and his position on some political issues.
Mr Babchenko had lived in the Ukrainian capital after receiving threats at home for saying he did not mourn the victims of a Russian military plane crash.
Writing in an article in the United Kingdom newspaper, the Guardian, explaining his decision to flee Russia, Babchenko said the campaign "was so personal, so scary, that I was forced to flee".