Investigation into golf cart accident that left NFL legend John Elway's agent dead remains open

The two were leaving a Stagecoach after-party, the outlet reported.

A spokesperson for Cal Fire told Fox News Digital Sperbeck sustained "serious injuries" and was transported to a hospital. He was initially listed in critical condition, but he died April 30.

Riverside County Sheriff Chad Bianco told Fox News Digital the case will remain open until all residents who may have video are contacted, but there's nothing indicating foul play.

"We determined the case would remain open until we contacted all residents who might have video of the path traveled.  All potential witnesses have been interviewed. There is no evidence or statement to indicate this is nothing more than a tragic accident," Bianco said.

The Riverside County Sheriff's Office Coroner's Bureau previously ruled Sperbeck's death accidental, saying his death was the result of blunt head trauma, according to a statement obtained by Fox News Digital.

The coroner's office said the injury happened when the "passenger fell from" the golf cart.

"I am absolutely devastated and heartbroken by the passing of my close friend, business partner and agent Jeff Sperbeck," Elway said. "There are no words to truly express the profound sadness I feel with the sudden loss of someone who has meant so much to me."

Sperbeck's family also released a statement.

"We are deeply saddened to share the passing of our beloved Jeff Sperbeck. He was a wonderful father, husband, brother, son and friend to many and will be profoundly missed by all," the Sperbeck family said. "We are grieving this unimaginable loss as a family alongside our dearest friends the Elway's and the many other clients Jeff called friends."

Fox News' Chantz Martin and Scott Thompson contributed to this report.