I want to know the answer to the following question:
Which historically significant communist activist was associated with the 1919 riots in which some of Popper's friends were killed?
All the background I'm provided with is that "The riot had, in fact, been part of a plan by which leaders of the Communist party with connections to Béla Kun tried to take power by a coup; Popper did not know about this at that time.". Is that enough to answer the question?