In this July 17, 2014 file photo, people walk amongst the debris at the crash site of a passenger plane near the village of Grabovo, Ukraine. (DMITRY LOVETSKY / AP)

KYIV, Ukraine — A Ukrainian court has unexpectedly released a key witness in the case of the 2014 downing of Malaysia Airlines Flight 17 over separatist-held eastern Ukraine.

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The appeals court in the capital Kyiv ruled Thursday that Volodymyr Tsemakh should be released from custody, pending further investigation.

Tsemakh was the commander of the separatists' air defense in the area where the plane was shot down five years ago.

Unconfirmed reports have suggested that Tsemakh is on the list of prisoners that Russia wants exchanged in return for freeing several Ukrainians jailed in Russia, including 24 sailors captured off Crimea in November.

Dutch prosecutors investigating the MH17 downing which killed all 298 people on board said earlier this week they would like to question him.

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