On 8 August 2014 these four investigating nations signed an agreement that the results of the investigation would not be published unless all four countries agreed.  This gave one of the prime suspects in the atrocity, Ukraine, an effective veto over any investigations result that attributed blame to them.  This is an astonishing situation and probably without precedent in modern air crash investigations.

Why the Secrecy on the Mh17 Investigation

http://www.counterpunch.org/2014/12/19/why-the-secrecy-on-the-mh17-investigation/