A judge in Adams County declared a mistrial Friday in the case of a man accused of killing a 13-year-old-boy and wounding three others in a 2018 shooting during a road rage incident in Westminster.

The 17th Judicial District Attorney’s office said Friday a key witness couldn’t travel from out of state to testify in person because of an emergency medical issue, prompting the mistrial. The judge set a new trial for Oct. 25.

The trial began Wednesday, but didn’t make it through jury selection before the court declared the mistrial.

Jeremy Webster is accused of opening fire after following four family members into a dentist office parking lot at West 80th Avenue and Sheridan Boulevard in Westminster on June 14, 2018. He allegedly was angry that Megan Bigelow, the mother of three children in the car, had tried to change lanes to pull over for an emergency vehicle.

Vaughn Bigelow Jr. died. Webster also allegedly shot Meghan Bigelow, her younger son Asa, and another man, John Gale, news outlets reported at the time. Meghan Bigelow’s middle son Cooper was unharmed.

Authorities arrested Webster on Interstate 25 near Castle Rock a few hours after the shooting.

Webster faces charges including one count of first-degree murder and four counts of attempted first-degree murder.

Denver Gazette news partner 9News previously reported that Webster admitted to the attack, saying he had mental health problems and had changed medication the day of the shooting. A psychiatrist said Webster has been diagnosed with bipolar disorder and prescribed anti-depressant and anti-psychotic medications, according to 9News.

He has pleaded not guilty by reason of insanity.

Trial proceedings begin for man accused in fatal Westminster road rage shooting