A landlord put on stage for a 'criticism meeting' with peasants, under the supervision of PLA soldiers.

The meaning of the text on the banner above the stage is not entirely clear:
公審惡霸牛闫王大曰 (Gongshen eba niu yan wang da yue)
The big day of the public trial of the evil tyrant ox-demon-king?
The big day of the public trial of the evil tyrant and cruel Niu?