Robledo, in the country illegally, also is being held under an order from immigration officials.
Police recovered the vehicle Robeldo is believed to have been driving described as a silver BMW model 3 Series in a garage at a Woods Cross residence.
Zaragoza-Valencia, 73, was struck Nov. 25 at about 7 p.m. while walking along 1000 West near 1700 South. Zaragoza-Valencia, who was thrown 75 feet upon impact, died the next day.
Instead of stopping to check on the victim, Robledo "fled the scene rapidly," according to a probable cause statement filed with the jail.
Formal charges are pending in connection with the victim's death.
Meanwhile, Robledo may be facing probation violations in another case.
In January 2012, he was charged with first-degree felony burglary after he and another man broke a window and entered a South Salt Lake home, stealing a guitar, paint ball gun and a tent before an answering machine came on and scared them away, according to 3rd District Court documents.
Robledo eventually pleaded guilty to lesser class A misdemeanor counts of wrongful appropriation and criminal trespass with intent to annoy or cause injury.
He was sentenced in September 2012 to 24 months probation, with credit for 90 days in jail previously served. Terms of his probation include completing 50 hours of community service, paying $265 restitution and incurring no new violations of the law.