We don’t know. Likely nobody knows. Just knowing about Ukrainians in general, the majority at least considers themselves Orthodox (either Ukrainian or Russian) or Catholic (a couple of varients) with a few Protestants (mostly Baptists.)
So we’re talking statistically, not imperical knowledge.
Ukraine and Kiev, but rioters and revolutionaries are not always simply reflections of the normal religious demographics.
We just don’t know, and no one cares, the article is about 3 men who died.