Important questions about the attack at the Crocus Concert Hall in Moscow

This video was originally uploaded to YouTube by UNIAN (Ukrainian Independent News Agency):
https://www.youtube.com/watch?v=dNu5Hvj5SUs

The video is provided as-is except adding English subtitles.

Yes, this is a UKRAINIAN media outlet and even though they claim to be independent, they obviously have their own bias given the current situation and the two years of war between the two countries.

However, the FACTUAL information provided in the video and the questions it raises are very important to consider.
The anti-Russian propaganda can be safely ignored... ;)