As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED ENGINE LOST POWER IN MODERATE LEVEL HOVER. AFTER HEARING 3 DULL THUMPS, THE NOSE YAWED AND ACFT BEGAN TO SETTLE. PERFORMED CONTROLLED LANDING INTO 20 FEET OF WATER. ACFT ROLLED INVERTED AND SANK. CAUSE CURRENTLY UNKNOWN. NTSB IS INVESTIGATING AT THIS TIME.