Task: Question Generation
Input (English): In the beginning of 1996, several human rights groups brought cases to hold Shell accountable for alleged human rights violations in Nigeria, including summary execution, crimes against humanity, torture, inhumane treatment and arbitrary arrest and detention. In particular, Shell stood accused of collaborating in the execution of Ken Saro-Wiwa and eight other leaders of the Ogoni tribe of southern Nigeria, who were hanged in 1995 by Nigeria's then military rulers. The lawsuits were brought against Royal Dutch Shell and Brian Anderson, the head of its Nigerian operation. In 2009, Shell agreed to pay $15.5m in a legal settlement. Shell has not accepted any liability over the allegations against it.
Output (English): Shell was accused of participating in the execution of which southern Nigerian tribal leader?