AN-26 was hit with a MANPADS which cannot target altitude at which civilian airliners fly. No one at the time thought that Russia was crazy enough to supply the rebels with BUKs.
While the previous aircraft were downed by MANPADS or AA, the AN-26 in question was flying at an altitude only reachable by a SAM. At the bottom of this article [1] is a good overview of the shot-down aircraft over east Ukraine in 2014.
[1] http://airheadsfly.com/2014/07/15/ukraine-latest-an-26-downi...