TWIN PEAKS – (INT) – The whereabouts of a German physics professor missing in the San Bernardino Mountains is unknown.

Sheriff’s spokeswoman Jody Miller says volunteer searchers are empty-handed.

“An extensive air and ground search was mounted Tuesday of last week. But, there were no signs of Mr. Krost.”

Alois Krost, 62, had been attending an annual conference at Lake Arrowhead. He’d been hiking with several others on the Pinnacle Trail when he complained of feeling fatigued.

Krost was described as an experienced hiker and hunter, but carried only one bottle of water with him.

Searchers scaled back their efforts after covering a 3.5 square mile area.

Story Date: October 13, 2013