Ukrainian officials say Belarusian journalist Pavel Sheremet was killed because of his professional activities in a contract killing.
Ukrainian Interior Minister Arsen Avakov said in Kyiv on February 8 the results of a pretrial investigation into Sheremet's death "lead to the conclusion that this crime was carefully prepared by a group of people."
"Investigators do not rule out that the order for the killing came from the Russian Federation," Avakov added.
Oleksandr Vakulenko, the deputy chief of Ukraine's National Police and head of its main investigative unit, said Sheremet's journalistic activities in Ukraine, where he lived, and Belarus and Russia "is considered in the first place" as a motive for his killing.
Sheremet, 44, was killed when the car he was driving to work was blown up in central Kyiv on July 20.
Jailed in Belarus in 1997 while recording a story on the Russian-Belarusian border, Sheremet was often critical of top political leaders and other government officials in his reporting.
He had also warned in the last blog post before his death that Ukrainian politicians who were former members of volunteer battalions that had fought separatists in eastern Ukraine could carry out a coup in Kyiv.
Vakulenko said an antipersonnel mine was used in the blast that killed Sheremet. He added that no one had yet been arrested for the killing.
Ukrainian Prosecutor-General Yuriy Lutsenko agreed with Avakov in saying that Sheremet's "killer was not alone. This is a group [of assassins] and we can see part of this group in the video [taken where Sheremet's car was parked before he drove it]."