Fox, 37, had stopped Roman's car because the vehicle allegedly was involved in a drug deal minutes earlier.
After his arrest, Roman told police, according to preliminary hearing testimony, that he grew angry at being pulled over because he thought "the only reason he was stopped was he was Mexican."
When Fox walked up and demanded his license and registration, Roman pointed the barrel of an AK-47 out his driver-side window and fired, he later told police.
Ruben Chavez-Reyes, who helped Roman elude police for a day, was sentenced last year to prison for up to 15 years.
Chavez-Reyes met Roman after the shooting, drove him to Salt Lake City and went with him to Beaver, where the two were arrested Jan. 6.
Chavez-Reyes, 37, pleaded guilty to obstructing justice, a second-degree felony, and third-degree felony counts of burglary and evidence tampering.