Investigators say Emile admitted to officers that she tried to hide the abuse by covering the child in makeup.
Emile told police she tried to hide the injuries so "they didn't look so bad," KSTU reported.
Some of the abuse was allegedly recorded on cellphone camera.
Police searched the cellphones of both parents and found videos of Costello and Emile taunting the toddler with food, removing it and then punishing her, asking if she was "evil," KSTU reported.
Another video allegedly shows Costello using the foot of an infant child to kick their daughter in the face, prosecutors said.
In a hearing in February, Ogden officers testified that the 3-year-old looked like a "Holocaust victim," with thinning hair, sunken eyes and little to no muscle, KSL reported.
The child appeared to look increasingly worse in the photos while her two other siblings appeared healthy.
Those children have been removed from the home.
Costello and Emile have ties to a gypsy community and have several alternative names and addresses in multiple states, according to KUTV.
Attorneys for Webster County filed a notice in Utah’s Second District Court on Tuesday, stating their intent to seek the death penalty against both Costello and Emile.
Both are charged with aggravated murder as a capital felony.