Judd was last seen on July 25, 2021, on a day hike from his camp, near Lower Merced Pass Lake, to Red Peak Pass.

Ficery was last seen on June 15, 2005, while hiking alone near the Hetch Hetchy Reservoir in Yosemite National Park, California. He had gone on a trail that goes around the north end of the reservoir, then he changed his mind and headed up to the Pacific Crest Trail. Ficery has never been heard from again. His family became concerned when he did not return by June 19, when his wilderness permit expired. On June 21, they called the park service and a search was launched.

Burke was a resident of Rothfamham, Dublin, Ireland in 2000. He traveled to San Francisco, California for a two-week vacation in April 2000. Burke reserved a hotel room near Yosemite National Park from April 4 through April 6. His family said he is adventurous and an experienced hiker.

Barnes was a resident of Cucamonga, California in 1988. He left Tenaya Lakes near Highway 120 east of Tioga Road in California at approximately 9:00 a.m. on July 5, 1988. Barnes planned to hike from the Murphy Creek Trailhead to Polly Dome Lakes in Yosemite National Park, which are located approximately three miles from Tenaya Lakes.

Stacy rode into an area of Yosemite with her father and 6 others where they reached a cluster of cabins, where people could rest up overnight. The group tied the horses and some of them went into the cabins to freshen up. After getting changed into different clothes Stacy left her cabin with the intention of photographing the lake, she had her camera with her.