There is a multitude of pictoral evidence available for those that want to see it. I have stopped sharing tweets and pictures on here - or anywhere - because the footage is upsetting. I reached my limit at the corpse of the teenage girl that had been raped, tortured, stripped and her back branded with a swastika before she was killed. There are pages and pages of evidence of killings and mass graves that have been verified by independants like Bellingcat and The Red Cross.
It is easy to find in minutes for any reasonable human being who isn't behind Russia's self-imposed firewall.