Nathan Haun was believed to have been walking home, roughly in the area between Payson and Spanish Fork, when he was struck by a pickup truck or SUV sometime between 4:30 a.m. and 5:30 a.m. on Saturday.
Preston and Tammy Haun do not personally know most of the potential witnesses all of them teenagers and neither did Nathan Haun, they said. A friend of Nathan Haun's brought him to the party, where investigators have said teens were drinking. That friend has not broken the silence either, Nathan Haun's parents said.
"To live the rest of our lives wondering what happened," Preston Haun said, " … that would just be more misery."
Nathan Haun had been getting his life on track, his parents said.
Though he stopped attending Spanish Fork High, he had earned his GED and was planning on going to art school, according to his sister. He had also landed a job at McDonald's that he enjoyed. He would get up at 5 each morning to go, hitching a ride to work with his dad.
"He was independent," Preston Haun said. "He wanted to pay for everything."
Their son was fun, happy and a comedian, Tammy Haun said. He liked his co-workers and returned from work saying he'd had a good day, she said.
The family set up the Nathan Haun Memorial Fund at Wells Fargo.
Investigators are talking to new people and revisiting prior interviewees, but the potential witnesses remain tight-lipped, Preston Haun said. Some people can offer a version of events, which will be consistent to a point, but then the stories diverge.
"It's a pain," Preston Haun said. "We just want to know if it was an accident."
In the meantime, detectives are pulling surveillance footage from homes and businesses in the area to see if they can find the vehicle that hit the boy. It would likely have Nathan Haun's DNA, Preston Haun said.
He hopes detectives can find more clues by enhancing a video of a vehicle driving near the spot where his son died. It passes by a camera shortly before the passer-by who found his body drove by the same camera.
The footage shows only headlights and taillights, but detectives may be able to figure out, at least, what type of vehicle it was and narrow their search, Preston Haun said.
Until then, it's a waiting game for the Hauns. Investigators come by their house about twice a day to check in on them and answer their questions.
"They've been very supportive," Preston Haun said of police.
Anyone who has information on this case is asked to call the Utah County Sheriff's Office at 801-404-1912.
Nathan Haun's family plans to hold his funeral Wednesday.
Tribune reporter Bob Mims contributed to this story.
Donations to pay for funeral costs can be made at Wells Fargo bank locations to the Nathan Haun Memorial Fund.