DENVER — An Uber driver was charged with murder Thursday in the fatal shooting of a passenger on a Colorado highway.

Denver District Attorney Beth McCann announced that Michael Hancock was charged after last Friday's killing of Hyun Kim. Police said it appeared there had been some kind of altercation before the shooting, although authorities have not disclosed a motive.

A partially redacted police report released the day of the shooting said a witness who called 911 told the dispatcher that Hancock told him that his passenger tried to attack him on Interstate 25 so he shot him.

The man passed the phone to Hancock but police said he later refused to discuss what happened without a lawyer.

Police said Kim, 45, was shot numerous times, and 10 spent cartridges were found on the shoulder of Interstate 25. Hancock's silver sedan was located across the highway after it crashed into a wall, police said. Kim's body was found lying on the floor of the car's front passenger seat.

Police said Hancock, 29, had trouble breathing after officers put handcuffs on him and was taken to a hospital for treatment.

Hancock's family says he was trying to defend himself. In online efforts to raise money for a lawyer, they describe him as a hardworking husband and father of two, a Christian and community volunteer.

Hancock, who does not have a criminal record in Colorado, worked as a driver for nearly three years but Uber removed his access to its app after his arrest.

"We are deeply troubled by the events in Denver, and our thoughts are with the families of those involved," Uber said in a statement Thursday.

Hancock, who is being held in jail without the possibility of posting bond, made an initial court appearance Saturday. He has not been asked to enter a plea and it's not clear whether he has hired a lawyer yet.

Uber policy bars riders and drivers from carrying firearms except in states that expressly prohibit companies from banning guns.

Colorado allows drivers to carry firearms to protect themselves and their property but Uber says the company's policy that bars drivers and riders from carrying firearms applies in the state..