The incident occurred around 3 a.m. local time on Friday on Interstate 25, according to the Associated Press. A witness who spoke to the driver, Michael Andre Hancock, 29, called 911 and passed the phone to the driver who identified himself to emergency dispatchers.

Police said that when they arrived at the scene, Hancock was having trouble breathing. They placed him in handcuffs and removed his semi-automatic pistol, and took him to the hospital for treatment. Hancock was arrested later on Friday morning and is being investigated for first-degree murder, according to the report.

The passenger, Hyun Kim, 45, was shot multiple times, according to police, who also found 10 spent cartridges on the side of the interstate across traffic lanes. Kim was pronounced dead at the hospital. Hancock declined to speak to investigators without a lawyer present and was being held at the Denver County jail without bond pending charges.

His father, also Michael Hancock, told KDVR that his son is married and a father, who works as a counselor at a troubled boys home and takes college classes. “He’s a Christian kid and he’s all about making the world a better place,” his father said. “I wish I had been that attentive to my kids.”

The Kim family declined to comment on the incident.

Uber said in a statement, “We are deeply troubled by the events in Denver today. Our thoughts are with the families of those involved.” The company also said it had removed Hancock’s access to the app.