Here is a link to a 2015 study from the University of Ottawa that evaluated available videos, eyewitnesses, ballistics data, and other information about the shooting of Euromaidan protestors in 2014. https://www.researchgate.net/publication/266855828_The_Snipers’_Massacre_on_the_Maidan_in_Ukraine
There has been virtually zero coverage of this question in the western media.
The official western narratives about the Ukrainian revolution assume that the fatal shots came from forces connected with elected president, Viktor Yanukovych. If the shots came from someone else the narratives collapse.
Why the apparent disinterest in a question of such importance?
Yes, and there has never been any trial in Ukraine.
If the Euromaiden massacre really came from right-wing groups allied with the US, the whole narrative about saving democracy in Ukraine gets turned on its head. The real story would be that democratically elected government was successfully overthrown by groups who were responsible for the massacre.
Political power grows out of the barrel of a gun. Mao Zedong
If the shots came from forces related to far-right Ukrainian-nationalist groups, they successfully ended the democratically elected pro-Russian government in Ukraine. They are arguably responsible for the deaths in the conflicts in Ukraine since then as well.
Your question assumes that Ukraine is a functioning democracy. The number of seats in parliament are irrelevant if it is not. Instead the real power may be with paramilitary groups.