A day after a National Park Service employee died in a fall at Timpanogos Cave National Monument, agency officials decided to halt cave tours through the weekend while they investigated the accident.

Rex Walker, a 58-year-old maintenance worker at the Utah monument, was killed in a fall of 500-600 feet down a steep, rocky slope Thursday. His death came just a day after an 11-year-old schoolgirl suffered a broken jaw and other injuries in a fall at the monument, Timpanogos Superintendent Dennis Davis said Friday.

In announcing the cave closure -- and closure of the steep, 1.5-mile trail that leads to the cave entrance -- Friday afternoon, Park Service officials said they were erring "on the side of visitor and employee safety." The temporary closure will provide time for experts coming to the monument to assist Timpanogos staff in determining the cause of the fatal accident, and to mitigate any risks that may be identified, NPS Intermountain Region Acting Director Mary Gibson Scott said Friday.

“We hope that the community and visiting public understand our need to know thoroughly how this accident occurred, and to prevent a potential re-occurrence,” she said from the region headquarters in Denver.

The fatality was the first at Timpanogos in four years.

Mr. Walker, whose family ties stretch back to the monument's first superintendent, was riding a small trail motorcycle from the cave's exit to its entrance to check on a lighting problem when he somehow drove off the precipitous trail, Superintendent Davis said. He had been working with crews involved in "rock scaling," a process in which rocks that appear loose on the mountainside above the trail are knocked free, when he received a call about lights going out in the cave, Superintendent Davis said.

While no one watched Mr. Walker drive off, some of the crew "heard a noise and turned and Rex wasn’t on the trail anymore," he said.

Immediately below the trail where Mr. Walker went off the side there's a drop of about 20-25 feet, the superintendent said, and after that a steep talus slope runs for about another 75 feet, followed by several more drops.

"I'm sure it was in the range of 500-600 feet that he went down this slope, this rock chute," said Superintendent Davis.

While the superintendent, an experienced climber, was able to rappel down to where the trail motorcycle lay about 100 feet below the trail, there was no sign of Mr. Walker, who had worked at Timpanogos for about four years. The man's body was soon found, though, by park personnel coming up from below.

The Utah County Sheriff's Office was continuing an investigation into the death, and the Park Service also was following up with its own probe, the superintendent said.

A young schoolgirl had a much more fortunate outcome Wednesday when she fell about 100 feet below the trail.

"From what we had heard, she was kind of fooling around with her friends and walking backwards. I’m kind of surprised she didn’t get hurt more than she did," said Superintendent Davis. “It sounds like she’ll be recovered completely in six or eight weeks.”

Along with breaking her jaw, the girl sustained injuries to her neck and shoulder, but they were not considered to be too serious, he said.

"It’s a dangerous trail because of the dropoffs," the superintendent said. "The two major hazards are rockfalls and falling off the trail.”

The paved trail climbs about 1,160 feet over a mile-and-a-half from the parking lot to the cave entrance. In some sections there's great exposure below the trail, as well as cliffs overhead. There are no hand railings along the route, though, because winter's heavy snows and rockfalls would require frequent repairs and replacements, according to Superintendent Davis.

There are some rock walls in sections, and park crews have painted red lines along the trail where people are not supposed to stop because they could expose themselves to rockfalls, he said.

“We've actually tried over the year to construct rock walls in what we consider the most hazardous locations," said the superintendent.

Tickets to enter the cave carry warnings, as do well-placed signs, Superintendent Davis said. Still, these accidents will make the staff re-examine its safety precautions and needs, he said.