The investigation considers the main version of the death of Major Hennadiy Chastiakov, who was an assistant to Commander-in-Chief of the Armed Forces of Ukraine (AFU) Valeriy Zaluzhny, to be an accident, however three more possible versions of what happened are being considered: a murder ordered by the Russian special services, a murder motivated by hostile relations, and an attempted premeditated murder of another serviceman from the senior officers of the apparatus of the Commander-in-Chief of the AFU.

"As for the death of the assistant to Commander-in-Chief of the Armed Forces of Ukraine, indeed, the State Bureau of Investigation has started a pre-trial investigation. Investigators are now familiarizing themselves with the materials of the case that the National Police has prepared," Communications Adviser to the State Bureau of Investigation (SBI) Tetiana Sapyan said on the air of the national telethon on Wednesday.

The criminal proceedings include four possible versions of what happened, she said, adding that the main version is that an accident occurred as a result of careless handling of an explosive device. However, there are three more versions, Sapyan said.

"The second one we can talk about [...] is that there could have been a premeditated murder and a completed attempt on members of his family, veiled as an unintentional murder or an accident, which was committed by order of the Russian special services with the aim of destabilizing the military and political situation in Ukraine," she said.

Also, according to the SBI Communications Adviser, there is a version of "the deliberate murder of Chastiakov, committed on the basis of hostile relations – revenge, jealousy on the part of colleagues."

Sapyan named another version of what happened as the attempted deliberate murder of another military senior officer from the apparatus of the Commander-in-Chief of the AFU.

She drew attention to the fact that the dominant version at the moment is an accident.

"To date, a number of examinations have been appointed, witnesses will be questioned, and all the circumstances that preceded these tragic events will be established," she said.

The SBI Communications Advisor also emphasized that the investigation into this case is under the control of the Bureau's leadership.

"The investigation will do everything to establish all the circumstances as quickly as possible and establish that he was involved and guilty if one or another version other than the main one is confirmed," Sapyan said.