RedactedNarrative: On 8/10/15, subject departed Callville Bay Marina (Lake Mead National Recreation Area) at approximately 0445 hours in his 2012 17'' 7" Bass Cat boat. Subject headed northeast through the narrows entering the Virgin Basin.  Subject was heading towards the area of East Point on the Arizona shore to do some fishing.  Subject''s vessel made a slight right hand turn and headed southeast.  At some point, Subject''s vessel made an abrupt right hand turn.  Subject was thrown from the vessel while not wearing a PFD.  Subject''s vessel proceeded to spin out of control for a period of time until the engine malfunctioned causing the vessel to drift southwest and then to the northeast where it was located near Middle Point Island.  
   
  At 1710 hours a passer-by noticed Subject''s vessel drifting off Middle Point Island.  The passer-by noticed that the vessel was still running with the throttle in the forward position (80-100%).  The engine cut off lanyard was hanging from the throttle indicating that Subject did not have it attached to himself.  The passer-by then called NPS to report the unoccupied vessel.  A second passer-by also reported the vessel but noticed that the vessel was turned off and throttle was in the neutral position.  It is still unknown who turned the vessel off and adjusted the throttle.  
   
  NPS rangers arrived on scene to begin an investigation and search of the area.  Subject''s vessel was photographed and transported back to Callville Bay Marina.  NPS rangers then took more detailed photos that revealed that the vessel steering assembly had come apart.  At that point the vessel was secured in the NPS fire station at Callville Bay.  On 8/12/15 the vessel was transferred to Nevada Department of Wildlife to conduct a vessel accident investigation.  On 8/19/15, the body of Subject was located in the same area where the vessel made the abrupt turn.  Subject''s body was recovered by a ROV from a depth of approximately 300 feet of water.  An inspection of Subject''s body revealed lacerations to the forehead and below the left eye.  Contusions to the left side of the face were also present. 
   
   Mohave County, AZ coroner was unavailable to respond so the body was taken into custody by Clark County, NV coroner for evaluation.  Coroner report is pending.  Injuries are consistent with a prop strike or contact with the vessel.  No blood was found in or on the vessel.  Subject''s vessel was equiped with all required safety equipment by Coast Guard regulation.  On 8/19/15 a survey was conducted on Subject''s vessel by Tri-State Marine Surveyors, Inc.  The survey revealed that the nylon locking nut and washer had somehow come off the hydraulic steering ram support bracket causing the engine to immediately swing hard to the left until it slammed against its own swivel stops.  The vessel then reacted by nearly instantaneously turning hard right causing the ejection of Subject.
   