DANA POINT, Calif. -- Horrifying surveillance video shows a sedan striking a bicyclist at a southern California intersection before the driver allegedly exited the car and assaulted the victim, who later died at a hospital.
The dramatic collision in Dana Point, which launched the bike and the cyclist into the air, occurred shortly after 3 p.m. Wednesday.
Footage of the moment of impact was captured by a Ring doorbell camera mounted in front of a nearby home.
According to authorities, the man behind the wheel of the car then stopped, exited the vehicle and assaulted the male victim with a knife.
"Upon arrival, deputies found Michael John Mammone, 58, a cyclist, lying in the intersection suffering from severe injuries," the Orange County Sheriff's Department said in a news release.
Mammone was transported to a hospital, where he died.
Mammone worked as an emergency room physician at Providence Mission Hospital in Laguna Beach. He worked as an ER doctor at Mission Hospital since 2011.
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In a statement Mission Hospital said: "We are stunned by this devastating tragedy. The entire Mission Hospital family is grieving over the loss of an incredible physician and friend. "
ABC7 spoke with a neighbor who declined to be interviewed on camera. She said her family heard what sounded like a "gunshot" before the attack. When they ran outside, she said, they heard the suspect uttering racial slurs about "white privilege."
A spokesman for the Orange County Sheriff's Department said investigators had not been told of that allegation.
"As of right now, no known relationship" between the victim and suspect, "and no known motive," sheriff's Sgt. Michael Woodruff said in an interview.
The suspect was later identified by authorities as 39-year-old Vanroy Evan Smith. He was detained by witnesses at the scene, which Woodruff described as "brave, heroic actions, from my understanding." "But at this time, again, all of this is encompassed in the investigation," the sergeant said.
Smith, of Long Beach, was booked into the Orange County Jail and charged with murder on Friday. Authorities say a knife believed to be used in the assault was recovered at the scene.
Smith also faces a sentencing enhancement for the personal use of a deadly weapon. He pleaded not guilty at his arraignment in the jail courtroom in Santa Ana.
"An innocent man is dead because he took a bike ride to enjoy a beautiful California day along the beach and he was hit with a car and stabbed to death by someone he apparently never met," said Orange County District Attorney Todd Spitzer. "The murder of a complete stranger in broad daylight for what appears to be absolutely no reason is the stuff of nightmares."
A pretrial hearing was scheduled for Feb. 14 in the Harbor Justice Center in Newport Beach.
Smith could face up to 26 years to life in prison if convicted at trial.