William Hasley, 78, collapsed while hiking near Nichols Canyon Road in Los Angeles’ Runyon Canyon on Saturday evening and died shortly after rescue attemtps. Hasley, a friend and biographer of former Olympian Caitlyn Jenner, was found by air rescuers at 6:42 p.m. and was declared dead a short time later. The Los Angeles County Medical Examiner’s Office has not yet released a cause of death.

Runyon Canyon’s Recent History of Tragedy for Jenner’s Circle

Hasley’s death follows the July 2025 fatal cliff plunge that claimed the life of Sophia Hutchins, Jenner’s confidante and manager. According to the New York Post, Hutchins fell 350 ft near Jenner’s Malibu home, an accident that shocked the public and brought renewed scrutiny to the star’s inner circle . The New York Post also reported that Hasley was found collapsed on the canyon trail, underscoring a pattern of sudden, unexplained deaths affecting Jenner’s close associates.

Hasley’s Multifaceted Career and Recent Teaching Role

Beyond his work with Jenner, Hasley was a screenwriter for Universal Pictures, Warner Brothers and 20th Century Fox, with credits on shows such as Swift Justice and Murder, She Wrote. At the time of his death, he was an instructor in screenwriting at UCLA,where he reportedly spoke to students on Friday before the incident. The Daily Mail cited a source saying he had no known health issues and was actively engaged in campus activities.

Unanswered Questions About the Cause of Collapse

The Los Angeles County Medical Examiner’s Office has not released a cause of death, leaving questions about whether a heart event, accident or other medical emergency was responsible. The LAFD spokesman noted that air rescuers lowered medical teams to the patient,but the outcome was fatal. No eyewitness accounts of a fall or injury were reported, raising speculation about an internal medical event.

Hasley’s Legacy in Sports and Writing

Hasley’s 1996 self‑help book, Finding the Champion Within, chronicled Jenner’s Olympic gold‑medal journey and highlighted their close friensdhip. The book, published by Simon & Schuster, remains a notable contribution to sports literature. His brief marriage to actress Robin Riker in 1987 and his involvement in charitable activities, such as soup kitchen volunteering, paint a picture of a man deeply embedded in both the entertainment and philanthropic communities.