A Texas man accused of killing two people while randomly firing his gun along an Oklahoma interstate was charged Monday with first-degree murder.

Jeremy Doss Hardy, 36, of Pasadena, Texas, was arraigned on the two counts in Custer County. Police have said the suspect shooter sped through three counties while firing from his pickup truck along Interstate 40, west of Oklahoma City, and hit at least four vehicles. He surrendered after a 25-mile chase early Thursday morning.

Court documents filed Monday say Hardy agreed to take a breath test that showed his blood-alcohol level at 0.16, twice the legal limit for driving. Investigators also recovered "multiple spent bullet casings" after searching his truck, along with other evidence "consistent with gunshots being fired from inside" his truck, according to the probable cause affidavit.

Hardy was initially jailed for driving under the influence. Prosecutors added the two first-degree murder charges during a hearing in Custer County, along with other charges, including assault with a dangerous weapon and use of a vehicle in the discharge of a weapon. He was ordered held without bond.

Authorities said the first victim, 45-year-old Jeffrey Kent Powell of Arapaho, was traveling with his wife, who was not struck. The second victim was 63-year-old Billie Jean West of Lone Wolf. Both victims were traveling along the interstate when they were shot.

The case was being investigated as possible road rage, according to the Oklahoma State Bureau of Investigation and the Custer County Sheriff's Office. The agencies said they had no indication the shooter knew the victims.

In an interview with The Oklahoman last week, Hardy's father, Robert Hardy, said the reports seemed out of character for his son. He questioned whether authorities may have stopped his son by mistake.

"It's definitely not the way he was taught or the way he's always been," Robert Hardy told the newspaper on Thursday, before charges were filed. "Weren't there a lot of black four-door pickups on the road? . That's a pretty common vehicle for this part of the country. I'm praying that that's not something he's capable of doing."

Josh Morris said his tractor-trailer was struck by bullets Wednesday night, with one round narrowly missing him. Morris said he thought a rock hit his cab when a pickup sped past him for the second time on I-40. But when he pulled over, he discovered it was a bullet. He said the round lodged in a metal plate inside the door.

"I heard a 'thunk' on the side of my door and he whizzed on by and went a distance," Morris told The Associated Press in a telephone interview Friday. "At that time, I didn't know how fortunate I was. I call it an 'Oh, Jesus,' moment."