EXCLUSIVE: Caitlyn Jenner's Close Pal Dead at 78 — Inside The Chilling Investigation as Authorities Work to Determine Cause

The sudden death of Caitlyn Jenner's close friend and biographer William Hasley has sparked new questions, with officials still unable to say exactly how the respected writer died, RadarOnline.com can exclusively reveal.

While news of the 78-year-old’s passing stunned those who knew him, authorities have yet to determine either his cause or manner of death, leaving the case officially open as investigators continue their review.

According to records reviewed by Radar, the Los Angeles County Department of Medical Examiner has classified Hasley's case as pending, with no final ruling released on what led to his death.

Hasley, a respected author and longtime screenwriting instructor with UCLA Extension, was found dead near Runyon Canyon on June 6. He was perhaps best known to many for co-authoring Finding the Champion Within alongside Jenner, forging a friendship that stretched beyond the page.

Known for helping tell the stories of others, Hasley’s own final chapter remains unwritten as officials continue piecing together the circumstances surrounding his death.

Radar has learned the Medical Examiner’s office is still actively investigating the case and has not provided an estimated timeline for when its findings will be completed. The publication has requested the final report and will receive notification once it becomes available.

As questions linger, Radar has also sought additional records from the Los Angeles Fire Department in an effort to shed more light on the emergency response and the events leading up to Hasley’s death.

At the same time, requests for comment have been submitted to UCLA regarding Hasley’s legacy as an instructor and to Jenner’s representative to offer the former Olympian an opportunity to reflect on the loss of her longtime friend and collaborator.

So far, UCLA has not publicly issued a statement regarding Hasley’s passing, and no official tribute has appeared on the university’s website.

Hasley’s influence extended well beyond Hollywood. Long before collaborating with Jenner, he built a successful career as a writer and educator, penning episodes of beloved animated series, including The Smurfs and Fat Albert and the Cosby Kids, while mentoring aspiring screenwriters through UCLA Extension. He is survived by his wife, actress Robin Riker, whose credits include The Bold and the Beautiful and numerous television and film roles.

Now, attention has shifted from his accomplishments to the unanswered questions surrounding his death.

Until investigators release their findings, the circumstances remain unclear, with both the cause and manner of death still pending.

For now, those who admired Hasley’s work are left waiting for answers as officials continue their investigation into the respected writer’s final moments.

Radar will continue following the case and update this story as additional records and statements become available.