“From memory, wasn’t Grigory beaten to death by the same people he had OTHER people beaten to death with?”
No, must have been someone else, but not enough clues for me to figure out who, though.
“Shortly after midnight, on the morning of August 25, Zinoviev and Kamenev were executed by shooting.”
https://en.wikipedia.org/wiki/Grigory_Zinoviev
I am thinking of the NKVD head who was arrested by the NKVD and beaten to death.