A Syrian group calling itself the General Foundation for Prisoners’ Affairs says it has the bodies of five Russians killed when their military helicopter was shot down this week—but it will only give them up if certain prisoners are released from Syrian jails. The Russian helicopter was shot down over Idlib province on Monday, and Russia’s defense ministry confirmed that all five people on board were killed. No group has claimed responsibility, and it is not clear if the group demanding the release of prisoners had anything to do with it. The group’s Thursday statement, seen by Reuters, demands that prisoners in government jails be released, along with prisoners held by Hezbollah. The group did not specify how many prisoners it wanted released, or which ones in particular. The group offered no details on how it obtained the corpses, but it included in its statement copies of what it claims are the identity cards of the five people killed.