NIAGARA FALLS - A 12-year-old Bronx girl swept away by the Niagara River below Niagara Falls had wandered well off an established trail to the water's edge while hiking with a group of campers, authorities said Thursday as helicopters and boats searched a second day for any sign of the child.

“It's frustrating, because it didn't have to happen,” said New York State Park Police Lt. Patrick Moriarty.

At first light, searchers conducted a grueling foot search along a two-mile stretch of the Niagara Gorge's rocky shoreline, scrambling up and down steep slopes to check small inlets and swirling eddies.

The girl, identified by park police as Magdalena Lubowska, apparently slipped from a sloped rock and was pulled by the swift current away from shore just before 1 p.m. Wednesday. She had been walking with about 20 other children who were staying at a Niagara Falls bed and breakfast that caters to Polish-American church and community groups in New York, New Jersey, Pennsylvania and Connecticut. Authorities said she and a handful of others went off on their own, venturing some 500 feet off a marked trail into treacherous terrain.

“There's an opening where the water runs between the rocks,” Moriarty said. “Somehow, they actually climbed over that and they got onto a rock that was a 45-degree angle and the girl slid down to the end of it. The part that's under water is completely moss-covered, it's just like grease, and once she started to slide and the water grabbed her legs, there was really no way for her to hang on.”

The child's parents and two other relatives arrived in Niagara Falls about 3 a.m. Thursday after driving across the state. They were expected to meet with search crews Thursday afternoon.

Police meanwhile, planned to consult with the Niagara County District Attorney about whether to pursue criminal charges against the man who was chaperoning the group. He was identified by police as Timothy Hedges, 23, the son of the bed and breakfast owner. A young adult man who answered the door at the three-story stone inn Thursday declined to be interviewed or give his name to reporters.

“It was not a professional tour guide. It was the young man who named himself a tour guide,” Moriarty said.

The gorge where the girl disappeared is a picturesque, narrow stretch of swirling green water with stone walls rising 200 to 300 feet on either side. The group began their hike at Whirlpool State Park, where the river rushes toward Lake Ontario after plunging over the Falls.

Much of the water churns white, though appears deceivingly serene in spots.

Magdalena and some others wanted to touch the water and put their feet in, Moriarty said.

“They climbed down through a series of boulders and rocks to get down to the water,” he said. “If you saw it, you would think to yourself no one should be going down through that.”

After Magdalena fell, the chaperone and two children used cell phones to call 911, touching off a search involving numerous U.S. and Canadian agencies, including the U.S. Border Patrol and Coast Guard.

Operators of sightseeing boats and helicopters were being asked to look out for the missing girl, who was wearing a pink top, shorts and sneakers when she disappeared into the water.