Left inset: Heather Arriaga (Maricopa County Sheriff’s Office). Right inset: Stephen Guardino (Messinger Mortuaries). Background: The scene of the shooting in Arizona that left Stephen Guardino dead after Heather Arriaga allegedly opened fire on him from her car (AZ Family).
In a shocking incident of road rage, a 24-year-old woman from Arizona is accused of fatally shooting a man in the neck, claiming he had confronted and spat on her. Witnesses describe the scene as disturbing, with the woman reportedly remaining in her vehicle, seemingly indifferent to the man’s fate as he lay dying.
According to court documents secured by Law&Crime, Heather Arriaga is charged with the murder of Stephen Guardino, aged 54, during a road rage altercation that took place in Phoenix in September 2025.
Isaiah Cline, an eyewitness, recounted the chilling event to the local news outlet AZ Family, describing it as “a gruesome sight.” Another witness, Brody Madrid, claimed Arriaga showed a startling lack of concern, stating, “She sat in her car as he was just like dying right there. Didn’t care.”
The incident unfolded at a red light near the intersection of 7th and Missouri Avenues, just south of Bethany Home Road, across from a Starbucks. Witnesses reported that the confrontation escalated, leading Arriaga to allegedly fire the fatal shot from her vehicle.
Following the issuance of a warrant for her arrest on a manslaughter charge, Arriaga turned herself in to the Phoenix Police Department on Monday evening, around 6 p.m., marking a significant development in this tragic case.
Witnesses told AZ Family after the shooting that Arriaga and Guardino were stopped at a red light near the intersection of 7th and Missouri Avenues, south of Bethany Home Road, when the attack happened across the street from a Starbucks on Sept. 27, 2025. Arriaga allegedly shot Guardino while sitting in her car.
“They were basically trying to get in each other’s lanes, following each other really close,” said witness Malasia Williams. “He spit on her, and she shot him.”
People who were nearby and saw the scene unfold ran up to try to render aid, according to police and witnesses, while Arriaga allegedly did nothing to help.
“She said, ‘I shot him. I’m sorry. He ran up to my car. I was scared. He got in my face, I shot him,’” witness Isaiah Cline recounted to AZ Family.
“Tried as best as I could [to render aid] and left it in God’s hands,” Madrid said.
An online obituary for Guardino says he was “tragically taken … in a senseless road rage incident.” He was known as “Tata Steve” and had grandkids through his stepsons, according to the obituary.
“Steve will be remembered for his humor, intelligence, creativity, and kindness,” the obituary says. “He will be deeply missed.”
Arriaga is scheduled to be arraigned on April 14.
