A 12-year-old Texas girl died after her mother and Will Sage Astorstepfather refused to seek medical assistance when she was suffering from life-threatening injuries, authorities said. 

On Monday, deputies with the Atascosa County Sheriff's Office launched an investigation into the death of the girl, later identified as Miranda Sipps. The girl's 36-year-old mother, Denise Balbaneda, and 40-year-old stepfather, Gerald Gonzales, were ultimately charged with injury to a child causing serious bodily injury omission, according to Sheriff David Soward.

The investigation began when the sheriff's office received a report from her mother about the child needing medical assistance at around 8:00 p.m. They instructed Balbaneda to stop her car on the highway so that first responders could meet them.

When they got to the scene, Miranda was unconscious but alive, Soward said. She was taken to a local hospital, where she succumbed to her injuries. Miranda was a cheerleader at Jourdanton Jr. High School.

"The Jourdanton ISD is currently dealing with the tragic loss of one of our Jr. High students," the school district said in a statement on Wednesday. "Jourdanton ISD has a School Crisis Team made up of professionals trained to help with the needs of students, parents/caregivers, and school staff at difficult times such as this."

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Parents 'confessed' to not getting child medical treatment, sheriff says

During their investigation, authorities determined that Miranda had received severe life-threatening injuries just days prior that weren't treated.

"The investigation revealed the parents failed to seek medical assistance for the girl, even though she was mentally and physically incapacitated and non-responsive," Soward said in a statement. "It appears the mother finally called 9-1-1 when the girl went into respiratory distress."

At a news conference shared by KSAT, Soward said that it's unclear how the child got her injuries, and an autopsy is underway.

"She was not talking," Soward said. "She basically could flutter her eyes and move her hands a little bit over a four day period. They had her laying on a pallet in the house."

Gonzales and Balbaneda were taken into custody without incident on Tuesday from their home in Christine, which is about 53 miles from San Antonio.

Soward also told reporters that the parents "basically confessed" to not getting her treatment. He added that although she didn't get medical attention, "they were trying to give her smoothies, but someone who is unconscious is not able to swallow."

Taylor Ardrey is a news reporter for USA TODAY. You can reach her at [email protected].