The two drove to a truck stop in Salt Lake County, where Newton choked the woman, the charges state.
The woman told police she was crying as she tried to fight off the attack. That's when Newton pulled out a handgun, held it to her head, told her to stop crying and raped her, according to the charges.
As they drove away from the truck stop, Newton said he "might have to kill her" because she "seemed like a girl that would cause problems for him," the document states. At a red light on Bangerter Highway, the woman opened the door, got out and ran away.
Salt Lake City police found two loaded weapons in Newton's bedroom and a "quick access gun safe" under the driver's seat of his truck, according to court documents.
Newton is being held in the Salt Lake County jail, with bail set at $1 million. He is scheduled to make his first court appearance Monday before Judge Ann Boyden.