The next day, the Fourth of July, the family was getting ready to barbecue ribs and watch fireworks, hoping Hartley would come home at any time.
Instead, they got a knock on the door from a police officer.
"The officer who came out said, 'I have bad news, he was hit by a car, and they just kept going,'" said Mathis as she wept.
Investigators said Hartley was walking northbound on the west side of Highway 395 in Victorville north of Dos Palmas Road when he was struck. Paramedics responded and pronounced him dead at the scene.
Hartley and Mathis had a fight Saturday afternoon and Hartley took off with the family car.
"I was just so upset with him because he left me here stranded, and I waited for him to call and he never did," Mathis said.
Mathis said she was also upset that Hartley had just spent $600 to buy a used Dodge Intrepid, a car she thinks broke down late Saturday night. She said he was probably drinking.
The family hopes the people responsible come forward.
"I just want the person to come forward and talk to us," said Jeannie Hartley, the victim's mother. "Maybe it was an accident. We are forgiving people, but it's wrong to leave."
"I just want these people to come forward, because I'm not going to take it as an accident," added Brittany Hartley, the victim's daughter. "But if they come forward, maybe I can live with that."
Detectives said evidence at the scene has provided investigators with leads as to the type of vehicle that struck Hartley.
Anyone with information regarding the death or the vehicle is urged to call Deputy James Snow at (760) 241-2911.