The former governor of Western Equatoria state, Joseph Bangasi Bakosoro, has been released.
Mr Bakosoro had been in arbitrary detention without charge or trial since December 2015, at the National Security Service headquarters in Juba.
According to family members, the leader was freed last evening.
This comes weeks after a human rights watchdog, Amnesty International, appealed to the government to either charge and try him in a court of law or release him.
His sister Dodo Bakosoro told Eye Radio early this month that his health situation was worsening.