Aug. 4 (UPI) -- Investigators are trying to determine what caused a helicopter to crash into the Tennessee River, killing one person on board.
Knoxville Fire Department spokesman D.J. Corcoran told reporters the victim's body has been recovered.
It's not yet clear if the victim was the pilot or a passenger.
The three others were rescued by a pontoon boat, officials said.
The National Transportation Safety Board is leading the investigation.