GRAND CANYON NATIONAL PARK, Ariz. (AP) — Authorities say a 67-year-old man has died after a motorboat flipped over inside Grand Canyon National Park.

Emergency medical personnel treated four people Saturday and transported them to the South Rim. Authorities say their injuries were not critical.

Park officials identified the man who died as Ronald Vanderlugt, but didn’t immediately release his hometown. They say Vanderlugt was on the fifth day of his trip.

The boat flipped in Bedrock Rapid, which rafting experts say is a large rocky island that divides the Colorado River into left and right channels.

An investigation will be conducted by the National Park Service and the Coconino County Medical Examiner.