Are you suggesting that you have access to data/info not available to the general public?
Most generally all findings and investigations by the NTSB is public domain at the conclusion of any given investigation. What is not readily available are the notes, written comments and other such types of details that is used to determine the final/probably cause of any given accident. However, even this type of information can be be accessed by the public if correct procedures are followed.
Only in certain accidents involving US military aircraft will finding sometimes be held from the public. Such as a midair between a military aircraft and a civil aircraft. Also it might interest you to know that accidents involving US government aircraft, such as the FAA, FBI, Forestry Service and US Marshal Service are not available for public view.
So in answer to your question, no.
None of which changes the fact that the NTSB called for the permanent grounding of all MU-2s.