A 16-year-old American girl fell over 300 feet to her death while hiking with her best friend's family in Switzerland, police said.

The incident occurred on Sunday around 10:30 a.m. while the group was hiking on the “Gorges Mystérieuses” hiking trail in Trient, Valais police said in a news release.

The unidentified teenage girl, "for reasons that are still unclear," fell around 320 feet down an embankment, police said. Despite the rescue service's attempt to save the girl, she was unfortunately found dead in the riverbed of the "Le Trient" below the hiking trail, according to the department.

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Father of girl's best friend tried to rescue her initially after fall, police say

The father of the family was rescued after he tried to find his daughter's best friend, police said. The man was unharmed after rescue workers freed him from a rock wall where he could not make any further progress, according to the release.

USA TODAY contacted the U.S. Embassy’s Public Diplomacy Office but has not yet received a response.

The public prosecutor's office has launched an investigation into the girl's death in cooperation with Valais police.