Detailed Instructions: In this task, a passage will be given and the goal is to generate a question about temporal relations based on that passage. A temporal relation describes the relation between two things with respect to time e.g., something happens/starts/terminates/... immediately/shortly/usually/... before/after/during/... something else.
Your question should include an event, or ask about an event, and should not be a yes/no question.
Q: Passage: But Steiner said that in banning the officials, Petric had "violated the constitution of Bosnia-Hercegovina." The trial opened in the eastern Bosnian town of Zvornik, in Serb- controlled territory, which was the scene of some of the most brutal "ethnic cleansing" of non-Serbs during Bosnia's 43-month war.
A:
What event has already finished?