There have been rumours that separatists removed evidence from the crash site. So far this was impossible to verify for oursides like citizen journalists. However new photos on internet could indicate someone removed evidence.
You might remember the photo of an aircraft part which was located near the wreckage of the cockpit. It took me a while to find out if this was a part of the Boeing 777 or something else. I found out it was a Boeing 737 actuator which was loaded on MH17 as cargo. It was loaded in the cargobay below the business class section of MH17.
The actuator has a clear hole in it. It is safe to assume this whole was made made at impact. The actuator is likely made of strong steel. So it seems likely the hole was made by fragments penetrating the forward cargo.
Here is a high resolution photo showing the actuator and the position in the wreckage.
At September 29 two photos of what seemed to be the same actuator were published on this website.
Now the problem is to find out if this actuator was indeed part of MH17 cargo. I could not find 100% sure similarities between the actuator on the crash site and the one in the car trunk. The actuator in the car trunk is much cleaner. Still the website makes an association with MH17. There could be multiple actuators part of the cargo of MH17.