FLAGSTAFF, Ariz. — A 16-year-old Boy Scout from Utah drowned while on an outing with his troop Wednesday at the Grand Canyon National Park.

Kreg Harrison Jr., of St. George, drowned in a pool at Mooney Falls in Supai Canyon, according to a statement from the Coconino County Sheriff's Office. The incident happened just after 2 p.m.

Kreg was part of the Green Valley 6th Ward Scout Troop 1800. There were 19 boys and 12 adults at the outing, according to the sheriff's office. He and a couple of other boys attempted to swim under the waterfall.

"Investigators describe the pool beneath the falls as about 5 feet deep with a very strong undercurrent beneath and in the immediate area of the falls. The boys saw Kreg struggle and go under the water. One of the other boys attempted to pull Kreg above the water, however the undercurrent was so strong that it almost pulled the second boy under as well," according to the statement.

A doctor who was with the group attempted CPR but could not revive him. Two other boys who were with Kreg became trapped behind the waterfall and the others had to make a human chain to pull them to safety.

The troop was scheduled to hike out of the canyon on Friday. A police helicopter lifted the troop out Thursday.