But Dr. Gayle Suzuki, who signed the report, said she could not rule out the possibility that instructor Erich Mueller might have experienced a "cardiac arrhythmia" or irregular heartbeat during the jump "which caused him to become unconscious and land in the water which eventually led to his drowning."

Mueller and Saori Takahashi were near death after rescuers pulled the pair out of the water about 100 yards off shore Jan. 6. It was estimated that the two had been under water for up to 30 minutes.

Investigators determined there were no mechanical problems with the tandem parachute the two used during the jump.