Rescuers in the U.S. Virgin Islands on Thursday expanded their search for a missing American medical school graduate whose backpack was found on a cliff, officials said.

Even though searchers are taking a fresh look for Lucy Schuhmann, 48, on remote cliffs of Ram Head, Virgin Islands National Park spokesman Thomas Kelley said rescuers do not believe she fell.

Most of the area below Ram Head is jagged rocks, not water, so if anyone had fallen off, rescuers probably would have found a body by now.

"There’s no evidence of it and we don't have any reasons to think that" Schuhmann fell, Kelley told NBC News. "You have to understand that there is no water under most of that area."

A backpack with Schuhmann's ID was found on top of Ram Head.

Schuhmann was reported missing Thursday, after her bags were found at an vacation rental property in Coral Bay on St. John, officials said.

Her rental car was found at a parking area in the Virgin Islands National Park, officials said.

Schuhmann recently graduated from the medical school at the University of Louisville, according to the school.