"Such circumstances could include vehicles with front-end damage, broken windshields, vehicles traveling at high or low rates of speed, or drivers stopping to look at vehicle damage," according to a news release.
The vehicle could have traveled along (but was not necessarily limited to) Main Street or State Road 198 in Payson; State Road 198 in Salem; Main Street in Spanish Fork; and Arrowhead Trail, 8000 South, Mill Road or Woodland Hills Drive in Utah County. The driver may have gone down side streets as well, according to the release.
Even if vehicles in the footage are not suspicious, investigators are still interested in reviewing any video with clear images of them on these roads, the release adds.
Investigators also ask anyone who owns a car repair, car wash, service station or windshield repair business to review their footage as well and report suspicious vehicles.
The sheriff's office is offering a $5,000 reward for information leading to the arrest and conviction of the suspect.
Detectives hope the incentive breaks the silence surrounding the Spanish Fork boy's death.
"It's a pain," Haun's father Preston said Tuesday. "We just want to know if it was an accident."
The investigators have been trying to enhance a video they already have of a vehicle driving near the spot where Nathan Haun 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.
Anyone with information is asked to call Detective Dan Thomas at 801-851-4024.