Everyone who potentially saw the tragic golf cart accident involving John Elway and his agent, Jeff Sperbeck, has been interviewed by cops … and there is still no evidence to suggest a crime occurred, TMZ Sports is told.

According to Riverside County Sheriff Chad Bianco, police officers have spoken to all parties who were in the area near where Sperbeck fell off an Elway-driven ride back on April 26 … and “there is no evidence or statement to indicate this is nothing more than a tragic accident.”

Bianco added in his Thursday statement to TMZ Sports, “We determined the case would remain open until we contacted all residents who might have video of the path traveled.”

The 62-year-old sustained significant injuries in the tumble … and he was pronounced dead on April 30. The coroner later determined Sperbeck passed away due to accidental blunt head trauma.

Initially, law enforcement did not get involved in the matter … as Bianco told The Denver Post none of the medical personnel who raced to the scene suspected wrongdoing. However, the sheriff added a probe was eventually opened following a “massive media inquiry” into the incident.

Elway has only spoken once publicly about the ordeal — writing in a statement on April 30 he was “absolutely devastated and heartbroken” over Sperbeck’s passing.