Galeongirl
Galeonbroad
If the rebels are innocent, I cannot conceive why they would restrict access for the reason I've already stated - it would be a publicity goldmine for them against Kiev. They would bend over backwards to ensure investigators find every shred of evidence against whoever did it. At worst, the rebels would look open, transparent, and efficient to the outside world; at best, it would incriminate their enemies and give a boost to the rebel cause.
Instead, by behaving in an obstructive manner, they are creating a distinct impression of guilt.
That's pretty much what I was getting at as well. I truly cannot see why else they would hold off the investigation this much. If they let everything happen as quickly as possible, it would benefit their position and cause instead. Right now, it's incriminating them more than ever.