"There was a lot of physical damage to this child," McGuire said.
McGuire said Ryan and Angela Andrews inflicted other abuses on Shelby, too, but did not elaborate.
Both charges are first-degree felonies and carry the possibility of life in prison. Ryan Andrews, 38, was in the Davis County jail on Friday in lieu of $500,000 bail. The jail was holding Angela Andrews, 35, without bail. Both will make their first appearance in 2nd District Court on Monday.
About 11:30 p.m. Tuesday, Shelby's 13-year-old brother called 911 saying the girl wasn't breathing. Emergency crews arrived at the Syracuse home and found Ryan and Angela Andrews performing CPR on Shelby. She was pronounced dead at the home.
Police say on the night Shelby died, her father and stepmother beat her with a belt and Ryan Andrews threw Shelby into a wall, puncturing the sheet rock. A medical examiner has told police Shelby died from blunt-force trauma.
Postmortem examinations found bruises on most of her body, police have said. The parents had been abusing the girl for about a year, police said.
Police say the couple believed Shelby was disobedient and suffering from bipolar disorder.
On the night she died, Shelby bit her stepmother, police said. But McGuire said Friday he doesn't know what spurred that night's beatings.
There is no evidence of abuse to the other three Andrews children, Shelby's brother, sister and stepbrother, McGuire said. Those children are staying with relatives.