The number of people confirmed killed in a school shooting in Uvalde, Texas, has risen to 21, according to The Associated Press.

Earlier, Sgt. Erick Estrada of the Texas Department of Public Safety told CNN that the children were likely between the ages of 7 and 9, and two adults are among the dead. The shooter is also deceased.

Estrada also offered new details about the events leading up to the horrific slaughter at Robb Elementary School, about 85 miles south of San Antonio.

According to calls to law enforcement beginning at around 11:20 a.m. local time, the gunman, who has been identified as an 18-year-old male resident of Uvalde, shot his grandmother at her home before heading toward the school in a large, dark truck. He crashed the vehicle in a ditch near the small campus.

Callers told law enforcement that he was seen exiting the truck carrying “some sort of rifle”, a backpack, and wearing body armor. The gunman made his way into the school building through a south facing door and began shooting, Estrada said.