Correct me if I am wrong but doesn't the location of where an incident or accident occurs, eventually determines which investigative authority has the responsibility to investigate, which can be delegated to another state if required?
I understand the IAC in Russia will publish the DME report and the NTSB would have the duty of investigating what happened at JFK. Given that both entities have far more experience in incident and accident investigation, the GCAA would merely play a supporting role.