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

Deputies in California will keep open an investigation into a golf cart accident reportedly involving Denver Broncos legend John Elway but say all witnesses have been interviewed, and nothing indicates foul play was involved.

TMZ reported John Elway was driving a golf cart at The Madison Club in La Quinta, California, April 26 when his longtime agent and friend, Jeffrey Sperbeck, 62, fell out and hit his head.

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.

CORONER REVEALS JEFF SPERBECK, JOHN ELWAY'S FORMER AGENT, CAUSE OF DEATH FOLLOWING GOLF CART CRASH

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.

'STRANGE' HANDLING OF JOHN ELWAY GOLF CART INCIDENT CALLED OUT BY EX-PROSECUTOR WHO SAYS MISTAKES WERE MADE

In a statement released after Sperbeck's death, Elway said he was "devastated," according to ESPN.

"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."

Sperbeck became Elway's manager in 1990. Among Sperbeck's clients were Pro Football Hall of Famers Ronnie Lott and Jim Plunkett, in addition to hundreds of other NFL players.

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