I think the possibility that this was a false flag done by Russia itself cannot be dismissed .
I have seen chatter in various Russian telegram channels indicating first hand accounts that:
Russia received multiple warnings about an impending attack but chose to ignore them.
The emergency exits of the concert hall were locked as the attack was underway.
The Fire suppression systems in the concert hall did not perform as expected when the fire started.
Security forces took very long time to arrive to the scene despite their major headquarters being very close by.
Moscow Police making arrests a few hours before the Crocus attack.
I also don't think the Russian public would have accepted FULL mobilisation prior to this attack.
Finally, working strictly on the “who benefits” principle, the one who actually stands to gain the most appears to be Putin himself.
The attack gives him the reason he needs to take most (if not ALL) of Ukraine and make it part of the Russian Federation.
From his perspective (which is understandable to be honest), this is the only way to GUARANTEE with 100% certainty that Ukraine will NEVER join NATO and will NEVER have NATO forces or installations (e.g. Bio-labs) on its soil ever again.
