A Texas school teacher allegedly shot her son to death while driving him to school Monday, according to authorities.

Sarah Elizabeth Hunt, a 39-year-old fifth-grade social studies teacher in Waco, Texas, is accused of fatally shooting her son 17-year-old Garrett Hunt, who was found dead in the vehicle with multiple gunshot wounds, KWTX reported.

Authorities said the shooting happened in Riesel, which is southeast of Waco. An affidavit stated the teenager was staying with his father when Hunt picked him up.

A person saw Hunt’s white minivan on the side of the road and called Riesel police. The vehicle was still running, and all of the doors were closed with the windows rolled up. (RELATED: Woman Shot And Killed After Group Says ‘All Lives Matter’)

“What have I done…this is not real,” she told the two people, according to the affidavit.

Authorities discovered several .40 caliber cartridge cases on the ground on the driver’s side of the vehicle, along with a .40 caliber pistol inside the car and a spare magazine, according to the affidavit.

Hunt is employed by the Waco Independent School District, who said they plan to place the teacher on administrative leave, according to the report from KWTX.  She will then have the opportunity to resign before the district starts the process of terminating her contract.

Chief Deputy David Kilcrease of the McLennan County Sheriff’s Office said Garrett Hunt was on his way to his first day of school as a new student at Riesel High School, and the family was in the process of moving into the town, the Waco Tribune-Herald reported.

Authorities said they are still trying to figure out what led to the shooting.

Hunt faces a murder charge and is being held in a local jail on a $500,000 bond.