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 "An event that happened in 1919 had a profound effect on him: During a riot, caused by the Communists, the police shot several unarmed people, including some of Popper's friends, when they tried to free party comrades from prison.". Is that enough to answer the question?
Answer: no