A court in Kiev has ruled Thursday to release a potential key witness in the 2014 downing of Malaysia Airlines Flight 17 as Ukraine and Russia gear up for a highly anticipated prisoner exchange.

Volodymyr Tsemakh had faced prison time for fighting on the side of pro-Russian rebels in eastern Ukraine, leading observers to speculate that a key witness could be held publicly accountable in the MH17 case. The Dutch-led MH17 investigation team said it wanted to interrogate Tsemakh amid reports that his case may have stalled the rumored Russian-Ukrainian prisoner swap.