His hiking partner tried to help him but also fell down the mountainside. By the time the partner was able to safely reach him, he found Casey dead. Other hikers witnessed the fall from across the lake and went to an area with cellphone service to report the incident. A search and rescue volunteer from the Ventura County Sheriff’s Office was first to respond and provide aid. Alpine search and rescue members from the Mono County Sheriff’s Office and a California Highway Patrol helicopter later responded to the location when weather conditions permitted. In July, a 28-year-old hiker from the...