Details of Disappearance
Greene was last seen in Mammoth Lakes, California on July 13, 2013. He was vacationing in California with friends, climbing in the Sierra Nevada mountains. His car developed mechanical problems and he dropped it off at a repair shop. He planned to drive to Colorado to join other friends for more mountain climbing when the car was repaired.
Greene last spoke to his parents on July 16. He said he was going to go out in the mountains for one more long day and that he expected to get his car back on July 18. He never picked up his car, never returned home to Pennsylvania and has never been heard from again.
Since his disappearance, his credit cards and phone have not been used. The last ping from his phone was on July 16; the ping indicated the phone was in the vicinity of the Ansel Adams Wilderness.
On July 21, the host of the campground where Greene was camping reported a "missing or overdue person" to the police; Greene had not paid for his campsite for three days. His camping equipment, food and clothes were still there, but some climbing gear was missing. The items left at the campsite were packed and put in storage. Greene wasn't actually reported missing until July 29.
Based on what was missing from Greene's belongings, it was possible to determine what he was probably wearing and what gear he had with him when he went missing. He didn't have any overnight gear on him.
Authorities found his copy of High Sierra: Peaks, Passes, and Trails, a mountaineering guidebook. Two pages, from the chapter about titled "The Minarets and June Lake", were missing. Greene often tore pages out of guidebooks for places he wanted to go, then replaced the pages in the book after his trip.
His destination may have been Mount Ritter, which was covered in the pages torn out of the guidebook. The trailhead is eight miles from the road, and phone service in the area is limited. If he had in fact tried to climb Mount Ritter and gotten lost or injured, he probably could have only survived three to five days without shelter.
Nearly a month after Greene went missing, a hiker found a pair of glasses resembling his in the Inyo Craters region. The glasses, however, did not match Greene's prescription; they were not his.
At the time of his disappearance, Greene worked as a math teacher at Nazareth Area High School in Pennsylvania. He attended Clemson University and graduated from Pennsylvania State University, and went on to serve as a Peace Corps volunteer in Papua New Guinea. He's described as an experienced, skilled and cautious mountaineer.
He has since been declared legally dead; investigators believe he met with an accident in the mountains, possibly a fall. His remains have never been found.