An Uber driver in Denver killed his passenger early Friday, telling a witness he had fired several times in self-defense, police said.

Michael Andre Hancock, 29, was arrested and held with no bond, according to Denver County Jail records. He is being investigated for first-degree murder.

The incident comes amid abuse allegations and questions over Uber’s ability to properly screen its drivers.

Gun owners can carry pistols in their vehicles without a permit in Colorado, though Hancock appears to have violated Uber policies.

Police say Hancock shot Hyun Kim, 45, with a semi-automatic pistol during a confrontation at 2:47 a.m. Friday, according to a partially redacted probable cause affidavit provided to The Washington Post.

His sedan smashed into a concrete barrier on Interstate 25 in south Denver. Blood was found on the highway near 10 spent .40 caliber shell casings and matched the car’s path, documents show.

Denver police spokeswoman Marika Putnam said Saturday that the ongoing investigation has yet to determine if Hancock fired while his car was in motion.

A passerby stopped and spoke with Hancock before calling 911, saying Hancock said he was attacked by Kim, documents show.

Arriving officers found Kim slumped over on the floorboard of the front passenger seat and provided aid until paramedics arrived, records show. Kim was pronounced dead at a hospital.

Officers handcuffed Hancock and removed a Ruger pistol from his waistband. Hancock then began to have trouble breathing and was taken to a hospital where he was treated and released, police said. It is not clear why he was having breathing trouble: The document is redacted in three places, including in the summary before police describe his difficulty.

Investigators noted several bullet strikes inside the passenger compartment. Hancock refused to make statements about the incident without an attorney present, records show.

Hancock does not have a criminal record in the state, the Denver Post reported. An Uber official said Hancock had been driving with the popular ride-hailing app for three years.

His father, also named Michael Hancock, told KDVR-TV he had a permit to carry a concealed handgun. Putnam said she was unsure if that had been confirmed.