There's no conclusive proof that this is what happened. No official investigation has taken place (or has been concluded) and Ukrainian authorities have shown time and again that there was no political will to really discover how the events unfolded. (Ukrainian authorities have also been "reprimanded" for this lack of investigation by the EU or UNHCR, can't remember now and I don't have time to look for a source).
There are several alternative reconstructions of the events, for example the one by Ivan Katchanovski[1] which has also published several hours of original footage on his YouTube channel[2]. I would suggest anyone with an open mind to take a look at those.
I would be really wary of making unsubstantiated claims like those on events that are this controversial.
[1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2658245