This is what Iran has said,"
Investigators will go over every square inch of the wreckage to determine the cause of the crash. Chemical analysis will be done to test for explosive residue. Small shards of metal will be analyzed to see if a MANPAD or missile may have hit the helicopter.
The results of those investigations will be the determining factor as to whether or not this was an accident, or a sort of Archduke Franz Ferdinand moment, that triggers what the assassination of the Archduke did; a World War." So all is not over yet.