Editor’s Note: This story has been updated with the results of an autopsy report for the child.

LA JOYA, Texas (ValleyCentral) — La Joya Police arrested a woman in connection with the death of the 5-year-old student who was found unresponsive inside of a vehicle at Dr. Americo Paredes Elementary last month.

According to records, Diana Trevino Montelongo, 37, was charged with criminal negligence homicide.

La Joya ISD police chief Raul Gonzalez confirmed the 5-year-old student was related to Montelongo.

Documents obtained by ValleyCentral from the Hidalgo County Sheriff’s Office confirm Montelongo was the aunt of the 5-year-old and had been responsible for taking him to school since the beginning of last school year.

Authorities said Montelongo is a teacher at Dr. Americo Paredes Elementary where her nephew attended.

On Aug. 25, Hidalgo County Sheriff’s Department received a call about an unresponsive child inside a vehicle. On that day, Montelongo said she took the child to school but he was asleep in the backseat. When she arrived at the school she forgot to take down her nephew. Video surveillance from the school show Montelongo entering the campus alone.

After school Montelongo went to check that her nephew got on the appropriate school bus but could not find him, a law enforcement narrative said. She went to check her vehicle and found her nephew unresponsive in the backseat.

The child was taken to the nurse’s station at the school where staff and medical personnel attempted cardiopulmonary resuscitation lifesaving procedures, but were unsuccessful.

On Aug. 26 an autopsy conducted at the Hidalgo County Forensic Center determined the cause of death for the 5-year-old was a heat stroke.

Montelongo was arrested on Thursday and booked on a $50,000 bond. She was released the same day.