^^^Correct^^^
NTSB is a government body whose sole mission is to investigate accidents and determine "probable cause" of the accident and issue "Safety Recommendations" to the FAA. This sometimes takes years, and I imagine they are taking a very close look at the engine (among other things). You can check the NTSB accident database to keep track of when/If they issue the Factual Report with Probable Cause.
This process has nothing to do with FAA accident investigation, whose mission is to determine whether one or more of the "9" things was involved in the accident. I won't list all of them, but some are:
Weather, Airworthiness, Pilot competency, Regulatory compliance, etc.
You can request a copy of the FAA's report as well as the NTSB Factual Report once it is completed.