An anonymous witness who spoke to a local ABC affiliate said the suspect who allegedly struck a biker before stabbing him to death in Southern California last Wednesday muttered about "White privilege" during the incident.

The neighbor, who declined to be interviewed on camera, said she and her family heard what sounded like a gunshot before the attack against emergency room physician Michael Mammone, 58, and then heard the suspect issue the racial slur, according to ABC7.

Mammone was killed by a motorist in an attack in the coastal city of Dana Point while he was on an afternoon bicycle ride last week, according to authorities. The suspect, who also allegedly stabbed Mammone, was identified as 39-year-old Vanroy Evan Smith after being detained by bystanders and arrested on suspicion of murder.

CALIFORNIA DOCTOR STABBED TO DEATH ON SCENIC BIKE RIDE REMEMBERED BY COLLEAGUES FOR SAVING ‘MANY LIVES’

Dr. Michael Mammone

Dr. Michael Mammone, 58, was killed last week by a motorist who struck his bicycle and then attacked him, authorities said.  (Providence Mission Hospital Laguna Beach)

The Orange County Sheriff's Department did not respond to Fox News Digital's request for comment by time of publication, but a spokesperson for the department told ABC7 that they had not been told of the racial slur allegation against Smith.

Sheriff's Sgt. Michael Woodruff told the outlet that "as of right now, [there is] no known relationship" between Mammone and Smith and "no known motive."

Providence Mission Hospital Laguna Beach, where Mammone had worked since 2011, said in a statement provided to Fox News Digital that it was "stunned by this devastating tragedy."

Suspect in fatal stabbing, Vanroy Smith

Vanroy Smith, 39, is accused of killing Dr. Michael Mammone last week. (Orange County District Attorney's Office)

"The entire Mission Hospital family is grieving over the loss of an incredible physician and friend," the hospital said. "We will honor Dr. Mammone’s dedication to our community and passion for medicine by continuing to provide exceptional care."

Orange County District Attorney Todd Spitzer also issued a statement following the incident. "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," Spitzer said.

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Dana Point, California

Michael Mammone was allegedly struck by a car and then stabbed by Vanroy Smith last week in Dana Point, California. (Heather Paul via Getty Images)

"The murder of a complete stranger in broad daylight for what appears to be absolutely no reason is the stuff of nightmares. This unspeakable act of violence will forever haunt those who were forced to witness it, and it will forever haunt all of those who loved Dr. Mammone," Spitzer added.

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Smith is being held on $1 million bail and is slated to appear in court on Feb. 14.

Fox News' Louis Casiano contributed to this report.