You're reading: Reports: Prisoner swap may be held up as Moscow wants MH17 case witness

A prisoner swap between Ukraine and Russia may be delayed because the Kremlin is demanding freedom for a key witness in the 2014 downing of the Malaysian Airlines flight MH17, two well-connected political commentators suggest.

Former lawmaker Mustafa Nayyem and journalist Yuriy Butusov each wrote on Aug. 31 that Moscow wants the witness, Volodymyr Tsemakh, to be part of the group exchange.

Tsemakh was kidnapped in late June by the Security Service of Ukraine (SBU) from Snizhne, a town in the Russian-occupied part of Donetsk Oblast. He was formally charged with terrorism by a Ukrainian court. But his arrest could be connected to the July 2014 downing of the Malaysian Airlines airplane over eastern Ukraine that killed 298 people. At the time, Tsemakh was the commander of a separatist air defense unit based in Snizhne, Bellingcat reported.

The Joint Investigation Team, comprised of investigative agencies from Australia, Belgium, Malaysia, the Netherlands, and Ukraine, found that a Buk missile used to shoot down the plane came from Russia. In June, the international investigative team indicted three Russian nationals and one Ukrainian for their role in the downing of MH17. They were declared wanted persons.

Read more: Ukraine, Russia prepare for first major prisoner swap

Ukraine and Russia have been negotiating their first large-scale prisoner swap, which may include high-profile political prisoners such as Ukrainian filmmaker Oleg Sentsov, 24 Ukrainian sailors arrested in the Kerch Strait, Volodymyr Balukh, Pavlo Hryb, and Mykola Karpyuk.

It was reported that the swap could take place at the end of August and that, in preparation for it, the men were transferred to a detention center in Moscow.